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Lecture 5A - Functional Dependency | Normalization | DBMS | Deepak Poonia

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everyone how are you

all so in this lecture we will study functional

functional

dependency this concept we will study in

start so let's see what is this

functional dependency this is another

type of Integrity constant we have

already seen many different type of

Integrity constants like referential

Integrity constant we have seen we have

seen what is I can say uh entity

Integrity constant domain Integrity

constant so this is another Integrity

constant that we need to study that is

functional dependency okay so you can

see this is another type of Integrity

constant defined on the SCH schema now

let's see what is this functional

dependency so let's start with one

example consider some school database

okay some Indian School database you

consider in which you have a table

student table in this student table

let's assume you have student ID student

name District state so these are the

attributes in this table now you tell me

one thing so this is your student table

this is the student table in this

student table you have student ID you

have you have student name okay and

there is a column there is a column

district there is a column district and

there is a column State okay so in this

in this relation you tell

me if two districts are same for example

if let's assume if I put Alpha here and

if I put Alpha here okay if districts

are same means in these two tles let's

assume this is your tle T1 let's call it

tle T1 and let's call it tle T2 okay now

you tell me if in these two tles if

District name is same then can you

guarantee that this state name will be

same please tell me can you guarantee

that state name should be same can I say

that this state name also should be same

please tell me in these two tles there

is a tle T1 there is a tle T2 in these

two tles if District name is same then

can I say state name should be same yes

yes or no if District name is same for

example I can say for example I can say

if jaur

jaur then what should happen then what

should happen you can see state name

should be same yes or no so I should put

Rajasthan here I should put Rajasthan

here okay so this is what I'm saying

that if you repeat the district name I

can say in two tles if District name is

same then state name should be same yes

or no so I can say that these also must

be same these also must be same do you

agree with me okay this is called

functional dependency this is called

functional dependency that if I tell you

the name of the district then

automatically you can tell me the name

of the state this is called functional

dependency okay for example if I tell

you the name of the district okay means

for example I say Mumbai then what will

be the name of the state state please

tell me if I tell you the name of the

district then you can tell me the name

of the state the name of the state will

be Maharashtra so you can see one thing

you can see one thing I'm telling you

the value of this column the value of

this column I'm telling you but you can

determine the value of this column do

you agree with me yes or no if I tell

you the value of this column if I tell

you the value of District then you can

determine the value of estate yes or no

okay so very simple point that if you

know the value of district for example

if you know that district is Mumbai then

the state name will be Maharashtra yes

or no okay so is this clear please tell

me so very simple point that I can say

this District this determines State yes

or no okay what I can say I can say this

District I can say this this District

this column this attribute this attribute

attribute

determines determines this attribute if

you know the value of District attribute

then you can find out the value of State

attribute okay so I can say this

District attribute determines the state

attribute yes or no now tell me can I

say can I say State attribute determines

District attribute for example if you

know the name of the state okay for

example if you know the name of the

state now can you say can you tell me

what is the name of the district can you

tell me no you cannot tell me also

another another question for example if

I tell you that here the the the state

name is same in these two t okay there

is a tle T1 there is a tle T2 this is

your tle T1 this is tle T2 in these two

Tes I'm telling you that state name is

same then tell me can I say District

name must be same please tell me in

these two tles can I say District name

must be same

they may or may not be same yes or no

they may or may not be same for example

this may be beta this may be gamma do

you agree okay so they may or may not be

same so this is what I'm saying that can

I say

State this state column if I tell you

the value of estate then can you

determine the value of District no you

cannot determine yes or no so I can say

this state

determines this state

determines District this statement is

wrong WR yes or no this statement this

statement is wrong okay I hope you

understood what is functional dependency

so remember here what is happening here

I can say if you know the value of this

column then you can find out the value

of this column so I can say this column

District column determines the state

column okay or I can say in two Tes if

you have same district value in two Tes

if you have same value for district then

in those tles you will have same value

for State yes or no no so this is the

complete idea so I can simply say that

District implies State okay yes or no I

can say that District if you know the

value of District then that implies

State then you can also find out the

value of state so I can say District

implies state is this clear please tell

me is this understood I can say District

determines State I can also say that

District determines State determines state

okay now what the definition what this

means this means that in all the tles

for all tles for all tles T1 T2 if I

give you tles T1 T T1 T2 remember T1 T2

these are the tles for all tles what I

can say I can say that if if see in all

tles I'm saying for all tles I'm saying

that for all tles I'm saying that if if

in these tles dist dist value is same in

these two tles in these two tles if

District value is same then what should

happen please tell me in these two tles

if District value is same if T1 district

is equal to T2 District then what should

happen then what should happen then I

can say T1 state that should be same as

T2 State yes or no so in two tles if

District value is same then in those two

tles State value also must be same okay

so this is the definition of functional dependen

dependen

I can say that this state is

functionally dependent on District okay

what I can say I can say I can say that

this this District functionally

determines State okay this District this

District functionally determines State

functionally okay determines state so

you can see this is the idea

functionally determines

State I can also say that state is

functionally depend dependent on

District I can also say the same

statement I can also say that state is

functionally state is functionally

dependent on State on District dependent on

district is this understood see this is

a very very very obvious thing I can say

very intuitive thing okay you can see if

you know the value of District then you

can find out the value of State I can

say state is functionally dependent on

District this is what we will say we

will say that state is functionally

dependent on District what it means it

means that in two tles if District value

is same then in those tles State value

will be same okay so this is the idea so

remember all these statements are same

read these statements all of them are

same okay so you can see District

implies State this statement is same as

District functionally determines State

this statement is same as District Det

DET mines state or I can say state is

determined state is determined by

District I can also say state is

functionally dependent on District I can

also say state is dependent on District

so you can see all of them these

statements all of them are same okay all

these statements you can see all these

statements they have the same meaning

they have the same meaning okay and we

will denote it like this all these

statements remember they are same all of

them are same statements okay and what

we how do we denote it we denote like

this that District implies State this is

how we denote okay this is how we denote

so I hope you understood this is the

idea of functional dependency this means

that state is dependent on District okay

you can see you can see this line state

is functionally dependent on District

okay so this is the idea I hope you

understood now let's see some more

examples please tell me if you know the

ifsc code then can I say you also know

the bank name means if I give you the

ifsc code if I tell you the ifsc code

then can you determine the bank name can

you determine the bank name please tell

me can I determine the bank name if you

know the value of ifsc code then can you

determine the bank name yes you can

determine see I can also say that in two

tles if ifsc code is same let's assume

this is your tle T1 this is your tle T2

now tell me here IFS code and here ifsc

code they are same okay let's assume

here also a here also a then can you

guarantee that in these two tles bank

name will be same please tell me in

these two tles remember T1 is a tle T2

is a tle these are tles okay now in

these two Tes if ifsc code is same then

can I say Bank name will be same yes

Bank name will be same yes or no this

will be

same so this is the idea okay so this

Bank name this also will be same I can

say say BB okay so this is the idea now

tell me if you know the bank name then

can you determine the ifsc code please

tell me if you know the bank name if I

tell you the name of the bank now can

you determine ifsc

code can you determine ifsc code no you

cannot determine yes or no okay yes or

no no you cannot determine so this you

cannot determine very simple Point okay

because you can easily see for example

if you have SBI Bank okay in these two

Tes you have SBI Bank this is your tle

T1 this is your tle T2 in these two Tes

you have SBI bank now it does not mean

that ifsc code will be same okay here

you can have some other ifsc code here

you can have some other ifsc code yes or

no maybe here you have something called

maybe SB

0012 okay or maybe here you have

something called sbin 00 34 yes or no so

is this clear so you can see if you know

the name of the bank you cannot

determine the value of ifsc code but if

you know the ifsc code if I tell you the

ifsc code then you can determine the

value of the bank okay so this is the

idea now can you give me a situation

where can you give me the this type of

situation can you give me that a does

not determine B and B does not determine

a means a does not determine B and B

does not determine a can you give me

this type of situation give me this type

of situation give this type of situation

can you give me where a does not

determine B and B does not determine a

for example name comma marks for example

you can say name you can say a name and B

Marks B you can take marks now tell me

if marks are same if two people have

same marks then can I say they have same

name please tell me if two people have

same marks can you say they have same

name so you can

see you can see name and marks okay in

two tles if I put same name okay let's

assume in these two tles I'm putting

same name here also I'm putting Z here

also I'm putting Z Now is it mandatory

that they have same marks see these are

two students these are different

students this zone is different this

zone is different now can I say they

will have same marks no they can have

different marks they can have different

marks now you tell me if I put same

marks in these two in these two tles if

I put same marks then can I say the

student name will be ZN can you

guarantee that a student name will be

Zone please tell me can you guarantee

that a student name will be zone no you

cannot guarantee maybe student name is

something else yes or no maybe student

name is Sono okay so this is the idea I

hope you understood okay so you can see

this is the situation where a does not

determine b b does not determine a if

you know the value of a then can you

determine the value of B no if you know

the value of B can you determine the

value of a no or you can see in these

two tles the value of a is same this is

your a this is your B in these two Tes

value of a is same but value of B is

different in these two Tes value of B is

same but value of a is different okay so

I hope you understood is this clear can

you give me a situation where a

determines B and B determines a can you

give me this type of situation can you

give me this type of situation where a

determines b b determines a this type of

situation can you give me can you give

me a determines b b determines a yes for

example a can be your AAR card

number a can be your AAR card number

let's assume this is your Adar number

and maybe B is your pan card number yes

or no is this clear so can I say a

determines b b determines a please tell

me for example if you have let's assume

this is your AAR card number this is

your pan card number okay now you tell

me if two people in these two if I put

the same AAR card number then can I say

they will have same pan card number

please tell me in these two tles in

these two tles if I put same Adar card

number same Adar card number then can I

say they will have same pan card number

yes they will have same they cannot have

different pan card right yes or no in

these two tles if I put same Adar number

same Adar number then you cannot have

different pan card number so I can say

they will be same yes or no similarly

Sim similarly if I put for example if I

put same pan card number in these two

tles in these two tles if I put same pan

card number then AAR card number also

will be same are you getting my point so

this is the situation where a determines

b b determines a okay I hope you

understood is this clear please tell me

is this understood okay so this is the

concept of functional dependency now let

me tell you the definition of functional

dependency you already understood what

this means functional dependency this

means that if a comma B are attributes a

is attribute B is attribute in a

relation R then when can we say a

determines B when can we say a

determines B A implies B A determines B

if and only if Whenever two tles have

same a value then those two tles must

have same B value yes or

no read this definition a comma B are

attributes in a relation R there is a

relation R in this relation R let's

assume a is a attribute B is a attribute

okay there can be more there can be more

now when can I say that a determines B

what is what is the meaning of a

determines B A determines B first of all

this how do we read it how do we read it

we read it that a determines B this is

how you read it a determines B you can

also read it a functionally determines B

you can also read like this a

functionally determines B okay

this is how you can read a functionally

determines B you can also say that b is

determined by a okay you can also say

that a implies B all these are same I

told you I already told you that all

these are same you can also say that b

is functionally dependent on a yes or no

B is functionally dependent on a

dependent on a okay so like this so

these are different different interpretation

interpretation

so what this means this means a

determines B now when can I say a

determines B when can I say a determines

B A determines B if and only if Whenever

two tles have same a value then those

tles must have same B value yes or no

Whenever two tles have same a value then

they must have same B value okay so this

is the idea so what this means remember

you have a relation R in which you have

attributes for example A B C D these are

the attributes now what the definition

of a determines B this will happen if

and only if this will happen if and only

if for all

tles this will happen if and only for

all tles for all tles T1 T2 this T1 T2

what are these These are tles remember

this T1 T2 these are tles okay so these are

are

tles now I saying that for all tles what

should happen for all tles this should

happen that

if if these tles have same a value okay

this T1 a is equal to T2 a if these two

tles have same a value then what should

happen tell me if these tles have same a

value these tles they have same a value

then they should have same B value yes

or no these two tles have same a value

then what should happen this would

happen that they have same B value okay

this T1 B is equal to t2b they have same

B value so I hope you understood so this

is the idea this is the definition of

functional dependency okay and how do

you read it this you read you can read

that a determines B okay so this is the

definition I can say a determines B if

and only if if and only if t1. a is

equal to T t2.

A this implies okay remember this means

that two tles have same a value then

what should happen this should happen

that they should have same B value they

should have same B value T2 do t1b is

equal to T2 dob this should have same B

value for all tles for all tles this

would happen this would happen for all

tles T1 comma T2 okay whatever tles you

take if they have same a value then they

must have same B value so this is the

definition of functional dependency I

hope you understood okay so is this

clear please tell me so you can see the

definition of functional dependency we

have seen now one important note I want

to tell you that is functional

dependencies are defined on the schema

they are not defined on the instances

remember functional dependency these are

defined on the schema do you remember I

told you that Integrity constant they

are defined on the schema yes or no when

we were discussing Integrity constant

for example referential Integrity for

example your entity Integrity domain

Integrity key constant basically all the

Integrity constant that we have seen I

told you that they are defined on the

schema all of them they are defined on

the schema they are not defined on the

inst es they are defined on the schema

so all the instances must satisfy them

yes or no you are defining this

functional dependency you are defining

on the schema now what should happen all

all instances must satisfy them okay

every instance must satisfy them is this

clear please tell me now tell me the

answer for this question in a school

database can we say that s do name

determines s do

marks please tell me

the answer is no you already know the

answer is no yes or no okay the answer

is no so very simple that in a school

database s. name cannot determine s do

marks but now consider this situation

one day you are taking test okay you are

taking this quiz let's assume this is

your weekly quiz 30 okay let's assume

this is your qu quiz 30 in this school

I'm talking about this school in this

school in this school one day you you

conduct this quiz quiz 30 you conduct

and let's assume this type of result you

get let's assume in this school this

happens just consider this situation

that name marks okay this happens that

these two students remember these are

different students for example let's

assume this is student ID 1 101 102 okay

let's assume these two students have

same name AA okay but their marks are

also same their marks are also same

let's assume okay and let's assume here

you have B and here you have 40 now you

tell me one thing is this possible just

tell me this point let's assume in this

school only three students are there

let's assume in this school only three

students are there this is the this is

the situation in this school only three

students are there now you tell me first

of all you tell me is this possible this

type of situation is possible right yes

of course this is possible so what we

call it we can call it instance yes or

no what we call it this is called

instance do you agree with me we can

call it instance i1 let's call it

instance i1 yes or no now you tell me in

this instance on this particular day

what will happen on this particular day

let's assume that there is another

student let's assume there is another

student okay that student is that that

student has the name a and let's assume

that student also has 30 marks now you

can see what will happen if this happens

if this happens then what people will

say people will say that in this quiz 30

if you are having same name then you are

having same

marks yes or no people will say this do

you agree with me yes or no so you can

see what people will say people will say

in this quiz in this quiz means okay for

this instance what they will they will

say they will say if you have same name

then you have same marks okay like maybe

you have seen uh on the Twitter on the

social media when World Cup matches are

going on okay what people will say

people will say that in 1992 Pakistan

lost uh many matches still Pakistan won

the World Cup this year also Pakistan

lost many matches so this year also

Pakistan will win the World Cup yes or

no this type of statements you can see

yes or no so these type of statement

they are instances do you agree with me

they are instances so please understand

that like for example on a particular

day on a particular day like this quiz

you are holding okay you are conducting

this quiz and coincidence this is a

coincidence can I say this is a

coincidence please please tell me can I

say this is a coincidence yes this is a

coincidence yes or no so by coincidence

this happens that let's assume whenever

you have same name then you have same

marks okay but tell me on other day what

will happen for example on the next day

in this quiz 31 what will happen what

can happen in this next day next day

what can happen for example this can

happen that this student is getting 50

marks okay so now on this day can I say

that if you have same marks you have you

if you have same name you have same

marks please tell me on this day can I

say please tell me on this day can I say

that if you have same name you have same

marks no so this is your instance I2

this is your instance I2 so now you tell

me now you tell me one day if you visit

this school you are visiting this school

on this day okay this is a coincidence

you visit this school on this day okay

and you see this chart this result you

see after looking at this result will

you say that in this school if you have

same same name then you have same marks

will you say this this type of statement

will you

say let's assume you visit this school

you visit this school okay just consider

this situation you visit you visit this

school okay so consider this scenario

let's assume you visit this school on

the same day on this quiz

30-day okay this quiz 30-day now you

tell me

now you tell me will you say will you

say that in this school in this school

I'm talking about school will you say

that in this school whenever you have

same name then you have same marks will

you say this no you will not say this

yes or no but you can say what you can

say you can say in this weekly CU 30 if

you have same name then you have same

marks yes or no that you can say agree

with me you can say that in this weekly

CU 30 if you have same name then you

have same marks that you can say so

please understand that if you visit this

school on this day then what you will

say then which statement is correct then

this statement is correct that in in

this quiz 30 in this quiz 30 same name

implies same marks or I can say name

implies marks yes or no name implies

marks means if you have same name then

you have same marks agree with me this

statement is correct or not please tell

me this statement is correct or not just

tell me this point in this quiz 30 I'm

talking about quiz 30 I am saying in

this quiz 30 if you have same name then

you have same marks this statement is

correct okay now you tell me is this

statement correct that in school in this

school in this

school will you say that in this school

if you have same name then you have same

marks will you say this please tell me

will you say this that in this school if

you have same name then you have same

marks no you will not say this yes or no

this you will not say agree with me this

statement will be false yes or no is

this clear this statement will be

false so please tell me did you

understand what I'm saying so this is

the point remember this is the important

point that functional dependencies these

are defined on schema they are not

defined on instances is this clear okay

is this point clear please tell me so

functional dependencies are defined on

schema they are not defined on the instances

instances

if you say that some functional

dependency is there then that should be

satisfied by all the instances remember

functional dependencies must be

satisfied by all the instances okay now

you consider this school situation you

have a school database and let's assume

on a particular day this quiz 30 is

there in this quiz 30 if you have same

name then you have same marks this is a

coincidence this is a coincidence so

what I can say I can say in this quiz 30

name name implies marks this is correct

okay in this quiz 30 name implies marks

this is correct but can I say in this

school can I say in this school name

implies marks in this school can I say

name implies marks this is not correct

this is not correct yes or no okay for

example this type of situation can be

possible next day you conduct quiz

number 31 now you can notice in this

instance name does not imply marks yes

or no name does not imply marks is this

clear in this instance name does not

imply marks look at this instance name

does not imply Marks here you have same

name but you have different marks name

is same but marks are different okay so

I hope you understood this point so very

simple Point remember can we say that

name determines marks the answer is no

we cannot say but it might be possible

yes or no it might be possible that in a

particular quiz in a particular instance

here this quiz means instance yes or no

it might be possible that in a particular

particular

instance s name if s name is same then

their marks are same this is possible

okay this is possible but it does not

mean that in the school on the schema s

name determines

marks okay I hope you understood this

point so remember this point you

remember see this this is interesting

point that if I give you instance given

an instance what I'm giving you I'm I'm

giving you instance if I give you some

instance then when can I say this

instance will satisfy functional

dependency when can I say this instance

will satisfy functional dependency if I

give you some instance when can I say

this instance will satisfy functional

dependency then you will check this

instance you will check this in instance

you will check and in this instance you

will check that if two tles have same

Alpha value then this should have same

beta value yes or no okay this instance

you will check but tell me if you check

the particular instance I give you a

particular instance you are checking

that particular instance if some

functional dependency is satisfied in

that instance then is it mandatory it

will satisfy for the schema please tell

me I give you a particular instance I'm

giving you okay a particular instance

I'm giving you on this instance if some

dependency is satisfied if this

dependency is Satisfied by this instance

then can I say this dependency is

Satisfied by the SCH schema no that is

not correct when can I say SCH schema

will satisfy this dependency when can I

say the SCH schema will satisfy the

dependency schema will satisfy if all

instances satisfy yes or no schema

remember SCH schema will satisfy when

can I say schema will satisfy this

functional dependency will be satisfied

by the schema if all instances satisfy

this yes or no do you agree with me this

functional dependency will be satisfied

by the SCH schema if all instances all

instances they satisfy this functional

dependency okay I hope this point is

clear now let's see this

example tell me the answer for this

question tell me one thing in this

question the question is asking for

instance or the question is asking for

schema see the question is saying

consider the relation instance this

instance is given to you and these are

the function dependencies that are given

to you the question is asking which of

these functional

dependencies they hold on the instance

the question is asking which functional

dependen is hold on the

instance the question is asking for

instance the question is not asking for

schema yes or no the question is asking

for instance so now you tell me for this

instance which functional dependencies are

are

satisfied look at this instance and tell

me which functional dependencies are

satisfied for example can I say this is

satisfied this a determines B is this

satisfied a determines B is this

satisfied this is not satisfied right

this a determines B this is not

satisfied why what is the reason you can

see here a value is same but B value are

different yes or no can you notice if

you know the value of a can you

determine the value of B please tell me

if you know the value of a can you

determine the value of B if I tell you

the value of a then can you tell tell me

the value of B you cannot tell me

because here you can notice here value

of a is zero here also value of a is

zero but here value of B is two and here

value of B is three yes or no so you can

easily see if I give you the value of a

can you tell me the value of B you

cannot tell me right so can I say that

instance can I say in this instance a

does not determine B yes or no a does

not determine

B in this instance a does not determine

B is this clear please tell me I can say

in this instance in this instance I can

say that a does not determine B okay if

I tell you the value of a you cannot

tell me the value of B for example if I

tell you the value of a I'm giving you

the value of a okay I'm giving you the

value of a I'm telling you value of a is

zero now can you tell me the value of B

can you tell me the value of B you

cannot tell me the value of B can be two

or three yes or no so you cannot

determine right you cannot determine we

cannot determine right is this clear so

if I give you the value of a can you

determine value of B you cannot

determine so I can say this is not this

does not hold this functional dependency

does not hold in this instance for this

instance for this instance this

functional dependency does not hold okay

is this clear let me know very simple

what about the next what about a

determining C what about a determining C

please tell me what can you say about a determining

determining

C so a determining B that does not hold

a determining B that does not hold what

about a determining C if I give you the

value of a can you tell me the value of

B sorry can you tell me the value of C

if I give you the value of a can you

tell me the value of C yes you can tell

me you can see whenever a value is same

then C value is also same yes or no

whenever a value is same then C value is

also same for example if I tell you the

value of a is equal to zero then can you

determine the value of C I tell you

value of a is zero then what will be the

value of C that will be four if I tell

you value of a is one then what will be

the value of C value of C will be five

so if you know the value of a then you

can determine value of B agree with me

yes or

no Okay so so I can say that in this

instance this is satisfied so remember

this is Satisfied by this instance this

is Satisfied by this instance okay so

remember this functional dependen is

Satisfied by this

instance okay this given instance will

satisfy this

dependency is this clear okay so this

dependency will be satisfied remember

this will be satisfied by this given

instance this is important that this

given instance is satisfying this

dependency okay what about the remaining

quickly tell me what about the remaining

what about what about B determining a

a what about B determining a please tell

me this B determining a this does not

hold if I give you the value of a uh

give you the value of B can you give me

the value of a if I give you the value

of B I'm giving you the value of B now

can you give me the value of a can you

give me the value of a you cannot

determine yes or no you cannot determine

if I tell you value of B is three then

can you tell me the value of a you

cannot tell me so you cannot determine

so I can say this functional dependency

does not hold for this instance yes or

no is this clear what about B

determining C what about B determining

C that also does not hold you can see

that also does not hold you can check

this B determining C that also does not

hold if I tell you the value of B then

can you tell me the value of

C you cannot tell me yes or no so this

also does not hold what about C

determining a what about C determining a

can I say C determines a yes C

determines a okay in this instance in

this instance C determines a what about

C determining B what about C determining

B no C does not determine B in this

instance is this clear please tell me

let me know is this clear so very simple

right yes or no now I want to ask you

now I want to ask you I'm not asking for

the instance okay now I will not ask for

the instance now I I'm asking which of

these functional dependencies hold on the

the

schema hold on the relation

schema hold on the relation schema are a

b c

now you tell me the answer which of

these functional dependencies do not

hold or hold okay either you tell me

hold or you tell me do not hold so which

of these functional dependencies hold or

do not hold on this on this schema I'm

talking about SCH schema now now I'm

asking for the SCH schema okay I'm only

asking for the schema now so now you

tell me now you tell me see one thing

you notice see one thing you notice in

this instance B determines a determines

C yes or no in this instance in this

instance a determines C yes or no please

notice in this instance a determines C

correct I can say in this instance in

this particular instance in this

particular instance a determines C okay

that is correct but does it mean that in

schema this will be satisfied does it

mean that in the schema this will be

satisfied what you can say

it does not mean that on the schema this

will be satisfied yes or no but we can't

say for the schema but we can't but we

can't say but we can't say that a

determines C or not on SCH schema on

schema on schema we cannot say yes or no

is this clear is this clear please tell

me on the schema I cannot say because

what can happen see this is possible

that on some other day what happens this

type of Entry comes yes or no see on

some other day maybe this type of Entry

comes okay so see what what can happen

this type of situation is possible that

on some other day Okay some more entries

come some more entries you do you are

doing some more entries and let's assume

this type of situation happens that the

value of a is zero and the value of C is

let's assume five the value of a is one

the value of C is let's assume six yes

or no is this clear please tell me okay

is this clear so you can see you can see

in this instance a does not determine C

okay in this instance I can say in this

instance in this instance I can say that

a does not determine C okay I hope you

understood so remember please understand

that this a determines C this is correct

for this instance in this instance a

determines C but we cannot say for

schema we cannot say this a determines C

this holds for the schema or not we

cannot say

okay maybe this is a coincidence do you

agree with me maybe this is a

coincidence that a determines C on this

schema yes or no on this schema a

determines C maybe that is a

coincidence okay so we cannot say that

this will uh this this hold for schema

okay we cannot say okay I hope you

understood now what about a determining

B what about this a determining B this

instance does not satisfy so can I say

schema will also not satisfy please tell

me this instance does not satisfy so can

I say schema will also not

satisfy SCH schema will also not satisfy

yes that is correct okay if instance

does not satisfy if this instance does

not satisfy then schema cannot satisfy

remember schema satisfies implies all

instances satisfy yes or no schema

satisfies not that some schema you have

some schema let's assume I giving you

this schema R okay a b c d something

like that now remember this point schema

satisfies schema satisfies a determining

B okay schema satisfies X determining y

for example X determining y if and only

if if and only if all instances satisfy

yes or no if and only if all instances

all instances should

satisfy all instances must satisfy

satisfy

must satisfy X determining y okay now

you tell me if some instance does not

satisfy then what you can say please

tell me if some

instance if some instance does not

satisfy if some instance does not

satisfy does not

satisfy uh this x determining y then

what you can say then what I can say if

some instance there is some instance

which does not satisfy does not satisfy

then what I can say then I can say

schema also does not satisfy yes or no

then I can say

schema does not does not

satisfy does not satisfy X determining y

yes or no then I can say that SCH schema

also does not

satisfy is this clear please tell me yes

or no is this clear let me know so very

simple point so remember this instance

this does not satisfy a determining B in

this instance I can say in this

particular instance what is happening in

this particular instance a does not

determine B so so I can say this

schema okay for this schema R what I can

say so for this schema R I can say that

a does not determine B is this clear

please tell me so very simple point now

you tell me if I say that this schema

does not satisfy a determines B

then is it possible that some instance

will satisfy is it possible see a schema

does not satisfy okay we can say that

schema does not satisfy a determining B

but can I say some instance can uh some

instance there can be some instance

which can satisfy yes okay some instance

can satisfy no problem okay is this

clear there can be some instance which

can satisfy for example this type of

instance you have let's assume let's

assume you have this type of instance

you can say this instance will satisfy

yes or no this instance will satisfy

okay anyway I hope you understood all

these points what about the

remaining so you can see for the schema

from the instance you what you can say I

can say that for the instance uh I can

say for the schema what I can say for

the schema definitely I can say this

does not satisfy okay this does not

satisfy I can also say this does not

satisfy right I can also say this does

not satisfy what about this one C

determining b c determining B this also

does not satisfy what about B

determining C this also does not satisfy

what about a determining C and C

determining a what about these they may

or may not yes or no see they may or may

not we cannot say for these we can we

cannot say anything we cannot say

anything yes or no for these we cannot

say anything is this clear please tell

me because I'm asking for schema I'm

asking for the schema so for these we

cannot say anything is this clear they

may or may not hold in the schema okay

yes or no may or may not hold for the

schema may or may

not may not hold for esema okay so they

may or may not hold for schema I hope

you understood all these points is this

clear so very

simple so you can see here for example

this instance is given to you in this

instance can you see that a determines C

in this instance can you see in this

instance I talking about this instance

in this instance can you see that a

determines C A determines C yes you can

notice whenever a value is same then C

value is same you can see whenever a

value is same C value is same whenever a

value is same C value is same okay so

very simple point so in this instance a

determines C in this instance you tell

me what about C determines a in this

instance tell me what about C determines

a c determines a that is not satisfied

in this instance you can see C value is

same but a value is not same yes or no

notice C value is same in these tles

look at these two tles these two tles in

these two tles you can see C value is

same but a value is not same okay so you

can see in this instance C does not

determine a what can you say about the

schema what you can say about the schema

for the schema also C does not determine

a and in the schema this may or may not

hold yes or no for the schema I'm asking

for the schema in the schema this may or

may not hold but I can say in the schema

this will definitely not hold yes or no

is this clear please tell me so I can

say in this previous in this

previous in this previous example what I

can say please tell me in this previous

example I can say that schema definitely

this definitely does not hold for the

schema I can say this C determines a

this definitely is not satisfied by the

schema okay this is not satisfied by the

schema because this is not satisfied by

the instance this is not satisfied by

the instance so I can say that this is

not satisfied by schema also by schema

also okay but what about a determine C

what about a determin c this may or may

not hold for schema yes or no this may

or may not hold for

schema may not hold for

esema okay this holds for the instance

this holds for the instance for this

instance this will hold this will be

satisfied but this may or may not hold

for the schema is this clear please tell

me understood so very simple all these

points are very simple okay now let's

see another that is functional

dependencies you can Define between set

of attributes also so far if you notice

we have defined functional dependencies

these functional dependencies we have

defined so far from attribute to

attribute yes or no agree with me okay

so far this was a single attribute if

you notice this was a single attribute

so far this was a single attribute this

was a single attribute correct so far if

you notice these were single attributes

but but remember this functional

dependency you can Define between set of

attributes also okay between set of

attributes also I can Define this so

let's see how to define this for set of

attributes for example let's assume this

is your schema you have a relation R

which has these attributes a b c d now

you tell me what this means that this

set of attributes this set of attributes

determines this set of attributes what this

this

means please tell me what this means

that this set of attributes this set of

attributes determines this set of

attributes what this means because

remember you can Define functional

dependencies between set of attributes

these functional dependencies you can

Define between set of attributes so what

this means this set of attributes

determine this set of attributes so what

that means that means that whenever a

tle this combination is same please

understand this means that

whenever this means that whenever this

combination is is same please understand

this combination whenever this

combination is

same whenever this combination is same

in two tles okay in in two tles then

what should happen please tell me in two

tles then what should happen so remember

whenever this combination is same this

combination this combination must be

same in two tles then what should happen

then this C value also must be same in

those tles then I can say this C must be

same in those

tles in those tles is this clear very

simple Point okay so this is very simple

idea I hope you understood similarly for

example you tell me what this means that

this set of attributes determines this

set of attributes what that means please

tell me this set of attributes

determines this set of attributes what

that means that means that whenever this

combination is same this combination

this entire combination whenever this

combination is same in two t then what

should happen then what should happen

then then what should happen then this

BC combination also should be same then

this BC combination also must be same

yes or no then this BC combination also

same must be

same okay understood is this clear

please tell me so very simple point so

remember just consider this you have a

relation this relation you have a b c d

okay now if I say that a determines C

what that means if I say AB determine C

now let's see what that means this AB

determine C this means that whenever

this AB combination is same in two Tes

if I give you two Tes T1 T2 and let's

assume this entire combination is same

this entire combination must be same

remember okay this entire combination

should be same for example if you put MN

here and MN here is the entire

combination same please tell me in these

two tles the ab combination is same or

not yes the ab combination is same okay

so whenever this AB combination is same

then this C this C value also must be

same okay this C value also must be

same okay is this clear what about this

please tell me if I put M here and if I

put let's assume something something

else for example let's assume if I put P

here now tell me let me know now is it

guaranteed that this should be Q please

tell me are these two tles having the

same AB combination these two tles look

at these two tles do they have same AB

combination they don't have same AB

combination they do not have same AB

combination so remember this may or may

not be same so now the C value can be

anything now the C value can be anything

no problem okay now this C value can be

anything whatever you want you can put

for example this can be R also okay this

can be R also or this can be Q also for

example if you do like this okay M and

let's assume here you have S then

remember here you can put Q also no

problem is this clear let me know please

tell me is this point

clear now let me tell you one thing now

let me tell you one thing that

remember this set of attributes this set

of attributes determines this set of

attributes okay

this you can also write like this a b

determin c okay so remember these two

things are same please notice these

notations are same notations is this

clear let me know is this point clear

these are same notations these two

things are the same okay but what is the

correct one like what is the formal one

I can say see both are correct both are

correct but this is formal and this is

convenient yes or no we do not want to

write this and this again and again yes

or no we do not want to write this again

and again so in for Simplicity we can

write like this so remember this is a

simple notation I can see this is a

convenient and simple notation I can say

this is a convenient and simple

notation and simple

notation okay and what is this and what

this this is the actual and formal

notation this is the actual and formal

notation is this clear

clear

okay so this is the actual and formal

concept I can

say this is the actual concept or I can

say formal concept and this is

convenient notation so remember these

two things are same is this point clear

please tell me these two things are same

for example for example if I give you

that this set of attributes determines

this set of

attributes okay this you can also write

like this that AB determines BC is this

clear okay these two things they are

same please tell me did you understand

okay both of these These are same is

this clear so we will use this because

as I told you this is simple notation

this is more convenient and simple

notation so we will use

this but you should understand what this

means but you should understand this

means that set of attributes AB

determines set of attributes BC is this

clear what this means this means set of

attributes ab and this means set of

attributes BC so these two are

same okay so very simple point so you

can see this set of attributes a

determines set of attributes BC what

that means that means whenever this

combination is same this combination

must be same okay so this is the simple

idea I hope you understood so remember

this AB determines BC what that means

let's see what that means that means

like this whenever this a combination is

same for example if I put one two one

two here if I put one two one two here

in in these two Tes AB combination is

same yes or no in these two Tes this is

your T1 tble T2 tble in these two Tes AB

combination is same so the C this BC

combination also must be same is this

clear AB combination is same so this BC

combination also must be same is this

point clear let me know AB combination

is same so this BC combination also must

be same understood this BC combination

also must be

same okay I hope you understood for

example in this T3 in this T3 if I do

this now tell me do we have same AB

combination do we have same AB

combination please tell me here do we

have same AB combination we don't have

same AB combination so now you can put

anything that does not matter okay so

you can see whenever AB combination is

same then BC combination must be same so

that's it so this is the idea so

remember this functional dependency you

can Define for set of attributes also

you can Define for set of attributes also

also

okay what this means let me know this AB

determines D what this means please tell

me this AB determines D what this means

this means that set of attributes ABC

this is set of attributes ABC determine

set of attributes

D okay and what this means that whenever

this combination is same then this

combination must be same okay whenever

this combination AB b c d e whenever

this combination is same for example 1

to 1 one to one when this combination is

same then remember this D combination

also must be

same okay is this clear very simple

point but if you change this AB

combination if you change this AB

combination then this then this D

combination can be anything now you can

put whatever you want okay now you can

put whatever you want is this clear

please tell me now you can put whatever

you want so I hope you understood all these

points is this clear all of them all

these points are they clear so this is

the complete concept of functional

dependencies okay so we will just use

ABC but what it means when I simply use

ABC what it means it means set

containing ABC is this clear whenever I

say ABC that simply means set containing

ABC but this is the notation we will use

this ABC notation we will use because

this is more

convenient okay this is more convenient

so we have seen what are the definition

of functional dependency okay so you can

see A1 to a n functionally determine B1

to BM when it will happen please tell me

A1 to a n okay this set this set

functionally determines B1 to BM when

when this will happen this will happen

when whenever this combination is same

this combination must be same if you

repeat this combination then you should

repeat this combination also okay so

this is the simple

concept so you can see okay you can see

whenever this this a combination is same

then this B combination must be same

this is the concept of functional

dependency this is the definition of

functional dependency that we have

already seen now let's move on tell me

question see this question is given to

you assume that following functional

dependency is hold this is already given

to you that the following functional

dependencies hold what this means when

you say these functional dependencies

are holding are they holding for an

instance or are they holding for a

schema please tell me see we are saying

the following functional dependencies

hold these dependencies they hold then

what we are saying yes we are saying

that they are holding for schema because

functional dependencies are defined for

schema agree or not yes or no is this

clear please tell me functional

dependencies are defined for schema

instances let me know functional

dependencies are defined for schema not

for instances so remember functional

dependencies these are defined for

schema these are Integrity constants

functional dependencies are Integrity

constants okay and all Integrity

constants are defined for schemas all

Integrity constants are defined defined

over es

schema over SCH schemas okay not

not on

instances is this clear so remember

these functional dependencies these are

also Integrity constants these are also

Integrity constants and what I can say I

can say that all Integrity constants

they are defined over schema okay so

very simple Point here these functional

dependencies they hold they hold on the

schema now the question is asking can

the following tle score exist can the

following tle score exist please tell

tell me can they

coexist this type of table can you get if you if you have this functional

get if you if you have this functional dependency then can you get this type of

dependency then can you get this type of table please tell

table please tell me if you have these functional

me if you have these functional dependencies on the schema on the schema

dependencies on the schema on the schema you have these functional dependencies

you have these functional dependencies then can you get this type of instance

then can you get this type of instance this instance you cannot get right yes

this instance you cannot get right yes or no this instance can you cannot get

or no this instance can you cannot get why what the reason what is the reason

why what the reason what is the reason because notice title determines depart

because notice title determines depart dep if title is same then Department

dep if title is same then Department must be same yes or no if title is same

must be same yes or no if title is same then Department must be same is it

then Department must be same is it happening is it happening no it is not

happening is it happening no it is not happening yes or no so very simple point

happening yes or no so very simple point that title determines Department you can

that title determines Department you can see title determines Department okay so

see title determines Department okay so if title is same then Department must be

if title is same then Department must be same if you have same title then

same if you have same title then Department must be same but that's not

Department must be same but that's not happening so remember this instance is

happening so remember this instance is not possible yes or no so I can say this

not possible yes or no so I can say this instance is not

instance is not possible this instance is never possible

possible this instance is never possible so very simple point this

so very simple point this instance is never

instance is never possible is never

possible is never possible okay dbms will not allow this

possible okay dbms will not allow this type of instance okay dbms does not

type of instance okay dbms does not allow this type of instance I can simply

allow this type of instance I can simply say dbms

dbms prevents okay dbms will prevent it okay dbms will prevent this instance

okay dbms will prevent this instance this instance will not be allowed by

this instance will not be allowed by dbms error will come okay if you try to

dbms error will come okay if you try to do this if you try to insert these tles

do this if you try to insert these tles remember if you try to insert these tles

remember if you try to insert these tles these three tles if you try to insert

these three tles if you try to insert then dbms will prevent dbms will give

then dbms will prevent dbms will give you

you error okay now this we have already seen

error okay now this we have already seen that functional dependencies these are

that functional dependencies these are defined on the schema so all the

defined on the schema so all the instances they must satisfy them all the

instances they must satisfy them all the instances every instance must satisfy

instances every instance must satisfy them this I told you okay so given

them this I told you okay so given instance you can check if functional

instance you can check if functional dependency holds or not if I give you

dependency holds or not if I give you some instance if I give you then you can

some instance if I give you then you can check for this instance some functional

check for this instance some functional dependency holds or not that you can

dependency holds or not that you can check but remember but remember if you

check but remember but remember if you want to say that on the schema the

want to say that on the schema the functional dependency will hold this

functional dependency will hold this functional dependency will hold on the

functional dependency will hold on the schema what that means that means all

schema what that means that means all the instances must satisfy this

the instances must satisfy this dependency is this clear okay so if you

dependency is this clear okay so if you want to say that some functional

want to say that some functional dependency holds for ES schema that

dependency holds for ES schema that means that all the instances every

means that all the instances every instance remember every legal instance

instance remember every legal instance should satisfy that functional

should satisfy that functional dependency okay so now you tell me the

dependency okay so now you tell me the answer for

answer for these tell me the answer for these

one so these we have already seen okay so you don't have to check these just

so you don't have to check these just check the remaining tell me this

check the remaining tell me this instance is given to you the question is

instance is given to you the question is asking which FD is hold on this instance

asking which FD is hold on this instance the question is asking for the instance

the question is asking for the instance which functional dependencies they hold

which functional dependencies they hold for the

for the instance what this means this means AB

instance what this means this means AB if AB combination is same then C

if AB combination is same then C combination should be same is it

combination should be same is it happening if I tell you what the value

happening if I tell you what the value of ab combination can you tell me the

of ab combination can you tell me the value of C if I tell you the value of ab

value of C if I tell you the value of ab combination then can you tell me the

combination then can you tell me the value of C so you can see whenever AB

value of C so you can see whenever AB combination is repeating then C is also

combination is repeating then C is also repeating yes or no whenever AB

repeating yes or no whenever AB combination is repeating C combination

combination is repeating C combination is also repeating you can easily see

is also repeating you can easily see okay here AB combination please notice

okay here AB combination please notice here AB combination is same here and

here AB combination is same here and here AB combination is same you can see

here AB combination is same you can see C combination is also same so if AB

C combination is also same so if AB combination is repeating then C

combination is repeating then C combination is also repeating I can say

combination is also repeating I can say whenever AB combination is same then C

whenever AB combination is same then C combination is also same so yes this

combination is also same so yes this holds for this instance

holds for this instance what about what about AC determining B

what about what about AC determining B what about AC determining B what about

what about AC determining B what about this AC determining B tell me if you

this AC determining B tell me if you repeat AC then is B repeating if you

repeat AC then is B repeating if you repeat AC no B is not repeating right

repeat AC no B is not repeating right for example if you repeat AC notice

for example if you repeat AC notice notice notice if you repeat AC if I

notice notice if you repeat AC if I repeat this AC for example if I give

repeat this AC for example if I give you if I give you this

you if I give you this 0404 then can you determine what is the

0404 then can you determine what is the value of B please tell me can you

value of B please tell me can you determine what is the value of B let me

determine what is the value of B let me know I'm giving you the AC combination

know I'm giving you the AC combination the AC combination I'm giving you that

the AC combination I'm giving you that is 04 now can you determine the value of

is 04 now can you determine the value of B we cannot

B we cannot determine we cannot determine what about

determine we cannot determine what about this BC determining a what about this BC

this BC determining a what about this BC determining a please tell me if BC

determining a please tell me if BC combination is same then can I say a

combination is same then can I say a combination is also same yes yes this is

combination is also same yes yes this is correct okay so I hope this is clear now

correct okay so I hope this is clear now tell me the same question is if I ask

tell me the same question is if I ask for the schema the same question I ask

for the schema the same question I ask for the SCH schema which functional

for the SCH schema which functional dependen is hold okay so you can see

dependen is hold okay so you can see which of these functional dependen is

which of these functional dependen is hold okay and do not hold and which do

hold okay and do not hold and which do not hold on

not hold on schema now tell me I'm asking for the

schema now tell me I'm asking for the schema if the same question I ask for

schema if the same question I ask for the scha then what will happen see then

the scha then what will happen see then you can say this definitely this will

you can say this definitely this will not hold yes or no definitely this does

not hold yes or no definitely this does not

not hold I can say this does not hold on

hold I can say this does not hold on schema also okay this does not hold on

schema also okay this does not hold on schema what about the

schema what about the remaining okay this does not hold on the

remaining okay this does not hold on the schema what about the remaining the

schema what about the remaining the remaining we cannot say yes or no the

remaining we cannot say yes or no the remaining for example this and this for

remaining for example this and this for these two we cannot say we cannot say

these two we cannot say we cannot say anything

anything we cannot say anything for these two we

we cannot say anything for these two we cannot say anything basically they may

cannot say anything basically they may or may not

or may not hold they may or may not hold on the

hold they may or may not hold on the schema may not hold on

schema may not hold on schema okay so these they may or may not

schema okay so these they may or may not hold on the schema we cannot say

hold on the schema we cannot say anything is this clear but definitely I

anything is this clear but definitely I can say that AC determining B that will

can say that AC determining B that will not hold yes or no this does not hold

not hold yes or no this does not hold this AC determining B

this AC determining B now let's move on tell me the answer for

now let's move on tell me the answer for this question can I give you this

this question can I give you this question as a homework please tell me

question as a homework please tell me this this question can I give you as a

this this question can I give you as a homework so very simple question

homework so very simple question instance is given to you you need to

instance is given to you you need to check which of the following functional

check which of the following functional dependencies are satisfied by the

dependencies are satisfied by the instance the question is asking for

instance the question is asking for instance or for the schema notice which

instance or for the schema notice which of the following dependencies are

of the following dependencies are satisfied by the instance the question

satisfied by the instance the question is asking for the instance

is asking for the instance okay remember the question is asking for

okay remember the question is asking for the instance so which functional

the instance so which functional dependenc is hold for the instance can

dependenc is hold for the instance can you tell me quickly what about this AB

you tell me quickly what about this AB determining C AB determining C what

determining C AB determining C what about this quickly tell me AB

about this quickly tell me AB determining C whenever AB value is

determining C whenever AB value is repeating can I say C value is repeating

repeating can I say C value is repeating no so this does not

no so this does not hold okay can you tell me about ABC

hold okay can you tell me about ABC determining a tell me can you tell me

determining a tell me can you tell me ABC determining a what about this ABC

ABC determining a what about this ABC determining a what about this ABC

determining a what about this ABC determining a what about

determining a what about this can this repeat please tell me only

this can this repeat please tell me only three attributes you have only three

three attributes you have only three attributes you have can this repeat this

attributes you have can this repeat this cannot repeat in the relational model

cannot repeat in the relational model you can see this is never repeating all

you can see this is never repeating all the tles They will be different yes or

the tles They will be different yes or no no two tles can be same agree with me

no no two tles can be same agree with me see these are the three attributes AB BC

see these are the three attributes AB BC no two tles can be

no two tles can be same no two tles can be entirely same so

same no two tles can be entirely same so so very simple this will this will hold

so very simple this will this will hold yes or no this will hold no problem okay

yes or no this will hold no problem okay so very simple this will

so very simple this will hold this will hold what about what

hold this will hold what about what about AB determining AC what about that

about AB determining AC what about that please tell me what about AB determining

please tell me what about AB determining AC what about AB determining AC whenever

AC what about AB determining AC whenever AB value is same can I say AC value is

AB value is same can I say AC value is same whenever AB value is same then can

same whenever AB value is same then can I say AC value is same whenever you have

I say AC value is same whenever you have AB value same can I say C value is same

AB value same can I say C value is same no okay so the remaining you can check

no okay so the remaining you can check okay is this clear so here you can

okay is this clear so here you can notice the ab value is same that is 62

notice the ab value is same that is 62 that is 62 62 but what about BC value

that is 62 62 but what about BC value but what about BC value sorry what about

but what about BC value sorry what about AC value but what about AC value what

AC value but what about AC value what about AC value you can see AC value is

about AC value you can see AC value is 6365 okay so you can see this does not

6365 okay so you can see this does not hold a determining AC this does not hold

hold a determining AC this does not hold okay so very easily you can do so this

okay so very easily you can do so this question you you can take as a homework

question you you can take as a homework now let's move on so I hope you

now let's move on so I hope you understood okay so this is the note that

understood okay so this is the note that is given to you you can see

is given to you you can see here this note is given to you that

here this note is given to you that Remember by looking at instance can you

Remember by looking at instance can you determine functional dependencies by

determine functional dependencies by looking at an instance notice by looking

looking at an instance notice by looking at an instance we might be able to tell

at an instance we might be able to tell which functional dependency do not hold

which functional dependency do not hold but we can never tell which which does

but we can never tell which which does not hold uh sorry which which do hold

not hold uh sorry which which do hold yes or no see this is this clear notice

yes or no see this is this clear notice by looking at an instance if you look at

by looking at an instance if you look at an instance then you can determine see

an instance then you can determine see you can determine that some functional

you can determine that some functional dependency does not hold but you can

dependency does not hold but you can never determine if some functional

never determine if some functional dependency

dependency holds yes or no is this clear please

holds yes or no is this clear please tell me so this is what we have already

tell me so this is what we have already seen you can see here so you can read

seen you can see here so you can read this very simple

this very simple okay a student is asking last one same

okay a student is asking last one same as a determining C that I will tell you

as a determining C that I will tell you okay see a student is asking is this

okay see a student is asking is this same as tell me this is same as can I

same as tell me this is same as can I say this is same as a determining C are

say this is same as a determining C are they same no they are not same they are

they same no they are not same they are different they are different okay but

different they are different okay but they are equivalent see they are

they are equivalent see they are different but we will see that from here

different but we will see that from here you can get here okay that we will see

you can get here okay that we will see don't worry that will come in the future

don't worry that will come in the future but remember these are different this

but remember these are different this functional dependency this functional

functional dependency this functional dependency they are different

dependency they are different dependencies is this clear they are

dependencies is this clear they are functional they are different fds they

functional they are different fds they are different fds is this clear so

are different fds is this clear so anyway this will come in future don't

anyway this will come in future don't worry okay this I will teach you in the

worry okay this I will teach you in the future that if you have this dependency

future that if you have this dependency then this implies

then this implies this also this implies this okay both of

this also this implies this okay both of them so remember this will imply this

them so remember this will imply this this will imply this so that we will see

this will imply this so that we will see don't worry but there are different

don't worry but there are different functional dependencies these two

functional dependencies these two functional dependency they are different

functional dependency they are different okay but they are equivalent these are

okay but they are equivalent these are different but they are equivalent okay

different but they are equivalent okay so that we will see in the future anyway

so that we will see in the future anyway so let's move on

now this is your gate exam question tell me the answer for this

me the answer for this question this is gate computer science

question this is gate computer science 2000 question consider the following

2000 question consider the following relational instance this instance is

relational instance this instance is given to you this instance is given to

given to you this instance is given to you the question is asking which of the

you the question is asking which of the following functional dependencies are

following functional dependencies are satisfied by the instance the question

satisfied by the instance the question is asking for the instance or for the

is asking for the instance or for the schema please tell me this question is

schema please tell me this question is it asking for instance or for the schema

it asking for instance or for the schema this is asking for the instance the

this is asking for the instance the question is asking which functional

question is asking which functional dependencies are satisfied by the

dependencies are satisfied by the instance by the instance yes or no which

instance by the instance yes or no which functional dependencies are satisfied by

functional dependencies are satisfied by the instance by this instance which

the instance by this instance which functional dependencies are satisfied so

functional dependencies are satisfied so now tell me the

now tell me the answer now tell me the answer let's

answer now tell me the answer let's check one by one XY determining Zed what

check one by one XY determining Zed what about this one XY determining Zed what

about this one XY determining Zed what about that XY does it determine Zed if

about that XY does it determine Zed if you have same value for XY in two tles

you have same value for XY in two tles then can I say you have same value for

then can I say you have same value for Zed in those tles means Whenever two

Zed in those tles means Whenever two tles have same XY combination then can I

tles have same XY combination then can I say those tles have same Z value tell me

say those tles have same Z value tell me you can easily see that no tles have

you can easily see that no tles have same XY combination so that is fine yes

same XY combination so that is fine yes or no if I give you the value of XY can

or no if I give you the value of XY can you tell me the value of Zed can you

you tell me the value of Zed can you determine the value of Zed see if I give

determine the value of Zed see if I give you the value of XY this combination if

you the value of XY this combination if I give you then can you determine can

I give you then can you determine can you determine the value of Zed tell me

you determine the value of Zed tell me if I tell you the combination this XY

if I tell you the combination this XY combination value if I tell you then can

combination value if I tell you then can you determine Zed can you determine Z

you determine Zed can you determine Z tell me for example if I tell you XY is

tell me for example if I tell you XY is for example if I tell you XY is 14 then

for example if I tell you XY is 14 then what will be Z

what will be Z what will be Zed if I tell you XY is 14

what will be Zed if I tell you XY is 14 then Zed will be two if I tell you XY is

then Zed will be two if I tell you XY is 15 then Zed will be three if I tell you

15 then Zed will be three if I tell you XY is 16 Zed will be three if I tell you

XY is 16 Zed will be three if I tell you XY is 32 then Zed will be two so can you

XY is 32 then Zed will be two so can you notice XY determines Zed do you agree XY

notice XY determines Zed do you agree XY determines Zed so yes this will hold yes

determines Zed so yes this will hold yes or no for this instance by this instance

or no for this instance by this instance Remember by this instance XY determining

Remember by this instance XY determining Z

Z holds okay so this will hold what about

holds okay so this will hold what about the next one what about Z determining Y

the next one what about Z determining Y what about Zed determines y will it hold

what about Zed determines y will it hold Zed determines y will it hold you can

Zed determines y will it hold you can see in these two Tes look at the first

see in these two Tes look at the first tle and last tle in these two Tes look

tle and last tle in these two Tes look at this tle and this tle here you can

at this tle and this tle here you can notice the Z value is same but the Y

notice the Z value is same but the Y value that is different yes or no y

value that is different yes or no y value is different okay so if I tell you

value is different okay so if I tell you the value of Zed can you determine the

the value of Zed can you determine the value of y if I tell you the value of

value of y if I tell you the value of Zed now can you determine the value of y

Zed now can you determine the value of y please tell me let me know if I give you

please tell me let me know if I give you the value of Zed now can you determine

the value of Zed now can you determine value of y we cannot determine we cannot

value of y we cannot determine we cannot determine yes or no okay yes or no we

determine yes or no okay yes or no we cannot determine so remember by this

cannot determine so remember by this instance I can say by this

instance I can say by this instance what I can say by this instance

instance what I can say by this instance I can say this does not hold okay not

I can say this does not hold okay not satisfied not

satisfied not satisfied okay this instance will not

satisfied okay this instance will not satisfy this okay what about the

satisfy this okay what about the remaining so you can see option A that

remaining so you can see option A that is gone option A is gone what about why

is gone option A is gone what about why determining Zed what about why

determining Zed what about why determining Zed can I say y will

determining Zed can I say y will determine

determine Zed yes y will determine Zed right yes

Zed yes y will determine Zed right yes or no you can see y will determine Zed

or no you can see y will determine Zed notice that y value does not repeat okay

notice that y value does not repeat okay so automatically this will determine z y

so automatically this will determine z y value Val does not repeat because y

value Val does not repeat because y value does not repeat so y will

value does not repeat so y will determine Zed also y will determine X

determine Zed also y will determine X also because y value does not repeat so

also because y value does not repeat so you cannot create a violation you cannot

you cannot create a violation you cannot create a violation tell me one thing how

create a violation tell me one thing how to create violation

to create violation of how to create violation of a

of how to create violation of a determining B what you need if you want

determining B what you need if you want to create violation of a determining B

to create violation of a determining B then what you

then what you need what you need if you want to create

need what you need if you want to create violation of a mining B then definitely

violation of a mining B then definitely you need this type of situation see this

you need this type of situation see this type of situation you need that two Tes

type of situation you need that two Tes have same a value but they have

have same a value but they have different B value yes or no is this

different B value yes or no is this clear please tell me so if you want to

clear please tell me so if you want to create violation of a determines B you

create violation of a determines B you must have this type of situation you

must have this type of situation you must have this type of situation is this

must have this type of situation is this clear you must have this type of

clear you must have this type of situation that if in two Tes you have

situation that if in two Tes you have same a value but you have different B

same a value but you have different B value

value okay this type of situation must be

okay this type of situation must be there if this type of situation is there

there if this type of situation is there then violation okay that implies

then violation okay that implies violation

violation of a implies B okay is this clear that

of a implies B okay is this clear that implies violation of a implies B this is

implies violation of a implies B this is the situation for violation of a implies

the situation for violation of a implies B now you can notice because y value

B now you can notice because y value does not repeat so can violation is

does not repeat so can violation is violation possible look at y value this

violation possible look at y value this y value does not repeat notice this y

y value does not repeat notice this y value does not repeat so can violation

value does not repeat so can violation exist can you create violation for y

exist can you create violation for y determining z y determining X you cannot

determining z y determining X you cannot create yes or no so very simple y

create yes or no so very simple y determines z y determines X okay what

determines z y determines X okay what about y z determining x what about y z

about y z determining x what about y z determining X again this value does not

determining X again this value does not repeat you can easily see this y z

repeat you can easily see this y z combination never repeats because y does

combination never repeats because y does not repeat see notice y does not repeat

not repeat see notice y does not repeat rep this y value does not repeat so this

rep this y value does not repeat so this combination also does not

combination also does not repeat because this combination does not

repeat because this combination does not repeat so you cannot create a violation

repeat so you cannot create a violation for this functional dependency for this

for this functional dependency for this functional dependency you cannot create

functional dependency you cannot create a violation so I can say this also will

a violation so I can say this also will hold so can I say option b that will

hold so can I say option b that will hold yes or no option b is

hold yes or no option b is correct option b that is correct is this

correct option b that is correct is this clear okay so remember this point this

clear okay so remember this point this simple point you understand that y value

simple point you understand that y value does not repeat so you cannot create

does not repeat so you cannot create violation for y determining Zed

violation for y determining Zed similarly y value does not repeat so you

similarly y value does not repeat so you cannot create violation for this

cannot create violation for this functional dependency now remember y

functional dependency now remember y value does not repeat so this

value does not repeat so this combination also does not repeat now

combination also does not repeat now remember if this combination does not

remember if this combination does not repeat then you cannot create violation

repeat then you cannot create violation for this functional dependency okay so

for this functional dependency okay so very simple for this question I can say

very simple for this question I can say answer will be option b what about

answer will be option b what about option C what about option C in option

option C what about option C in option see this x does not determine Zed let's

see this x does not determine Zed let's check can I say x determine Zed can I

check can I say x determine Zed can I say x determine Zed no you can notice X

say x determine Zed no you can notice X does not determine Zed yes or no X does

does not determine Zed yes or no X does not determine Zed so option C is also

not determine Zed so option C is also wrong what about y determining X that

wrong what about y determining X that will hold y determining X will hold but

will hold y determining X will hold but what about x z determining

what about x z determining Y what about x z determining y please

Y what about x z determining y please tell me what about x z determining y

tell me what about x z determining y can I say x z determines Y no because

can I say x z determines Y no because you can easily see you can easily see x

you can easily see you can easily see x z 13 x z 13 yes or no look at these two

z 13 x z 13 yes or no look at these two tles look at these two tles x z is 13

tles look at these two tles x z is 13 but what the value of

but what the value of y so you can see in these two tles x x z

y so you can see in these two tles x x z combination is same but y value is

combination is same but y value is different okay so what I can say this is

different okay so what I can say this is also not correct so what the final

also not correct so what the final answer the final answer is option b is

answer the final answer is option b is this clear the final answer is option b

this clear the final answer is option b so very simple point now let's move

so very simple point now let's move on so we have seen the definition of

on so we have seen the definition of functional dependency the concept of

functional dependency the concept of functional dependency we have seen now

functional dependency we have seen now the next topic is types of functional

the next topic is types of functional dependency there are two types of

dependency there are two types of functional dependency one is Trivial

functional dependency one is Trivial functional dependency another is

functional dependency another is non-trivial functional dependency these

non-trivial functional dependency these are the types of functional dependency

are the types of functional dependency now let's see what is the trivial

now let's see what is the trivial functional dependency trivial the name

functional dependency trivial the name itself is telling you trivial trivial

itself is telling you trivial trivial means this will always be

means this will always be true trivial functional dependency okay

true trivial functional dependency okay trivial functional dependency what is

trivial functional dependency what is Trivial let me tell you one thing this

Trivial let me tell you one thing this will this will help you in every in

will this will help you in every in every subject this will help you in

every subject this will help you in every subject what is a trivial fact

every subject what is a trivial fact please tell me what is a trivial fact

please tell me what is a trivial fact trivial fact is which is either always

trivial fact is which is either always true or always false okay remember

true or always false okay remember trivial when can I say some statement is

trivial when can I say some statement is Trivial when can I say some statement is

Trivial when can I say some statement is trivial trivial fact means either this

trivial trivial fact means either this is always true either this is always

is always true either this is always true either this will be always true or

true either this will be always true or this will be always

this will be always false okay either this will be always

false okay either this will be always true or this will be always false is

true or this will be always false is this

this clear okay so this type of fact is

clear okay so this type of fact is called trivial fact for example if I say

called trivial fact for example if I say for example if I say man is man okay now

for example if I say man is man okay now tell me man is man this is a trivial

tell me man is man this is a trivial fact yes or no this will always be true

fact yes or no this will always be true yes or no this is always true man is man

yes or no this is always true man is man dog is Dog okay I can say dog is Dog so

dog is Dog okay I can say dog is Dog so you can see that these things are always

you can see that these things are always true so because this statement is always

true so because this statement is always true I can say this is

true I can say this is Trivial this is Trivial right this is

Trivial this is Trivial right this is Trivial similarly if I say dog is cat

Trivial similarly if I say dog is cat okay or I can say dog is not dog okay if

okay or I can say dog is not dog okay if I say dog is not dog if I say dog is not

I say dog is not dog if I say dog is not dog now this is Trivial this is always

dog now this is Trivial this is always false okay so this is just an analogy

false okay so this is just an analogy okay don't get into it but I'm saying

okay don't get into it but I'm saying trivial fact that means something which

trivial fact that means something which is either always true or something which

is either always true or something which is either always false either it will be

is either always false either it will be always true or it will be always false

always true or it will be always false now let's see what is Trivial functional

now let's see what is Trivial functional dependency trivial functional dependency

dependency trivial functional dependency now you consider this type of functional

now you consider this type of functional dependency you consider a determining a

dependency you consider a determining a can I say this will always hold in every

can I say this will always hold in every relation whatever data I give you

relation whatever data I give you whatever instance I give you can you say

whatever instance I give you can you say this will always hold please tell me can

this will always hold please tell me can I say

I say that whatever instance I give you

that whatever instance I give you whatever whatever whatever relation I

whatever whatever whatever relation I give you whatever relation I give you

give you whatever relation I give you whatever instance I give you can I say

whatever instance I give you can I say this will always hold yes this will

this will always hold yes this will always hold can you prove it can you

always hold can you prove it can you prove it can you prove that this will

prove it can you prove that this will always hold see this will always hold

always hold see this will always hold please note this will always hold in

please note this will always hold in every

every instance in every instance of every

instance in every instance of every relation

relation yes or no this will always hold in every

yes or no this will always hold in every instance of every relation so remember

instance of every relation so remember this thing will always hold this

this thing will always hold this statement will always hold in every

statement will always hold in every instance of every relation so that is

instance of every relation so that is the reason this is called trivial and

the reason this is called trivial and can you prove it yes very simple see in

can you prove it yes very simple see in two tles if I give you the same a value

two tles if I give you the same a value can you give me the value of a if I give

can you give me the value of a if I give you the value of a can you give me the

you the value of a can you give me the value of a tell me tell me tell me if I

value of a tell me tell me tell me if I give you the value of a then can you

give you the value of a then can you tell me the value of a yes yes or no

tell me the value of a yes yes or no agree very simple right very simple

agree very simple right very simple point if I tell you the value of a I'm

point if I tell you the value of a I'm giving you the value of a can you

giving you the value of a can you determine the value of

determine the value of a see what this means see what this

a see what this means see what this means this means that given value of a

means this means that given value of a can you determine value of a given given

can you determine value of a given given the value of

the value of a given the value of a can we determine

a given the value of a can we determine value of

value of a can we determine value of a yes you

a can we determine value of a yes you can do that can we determine value of

can do that can we determine value of a okay yes you can do that okay yes or

a okay yes you can do that okay yes or no so for example if I tell you that

no so for example if I tell you that value of a is four then tell me can you

value of a is four then tell me can you give me the value of a I tell you value

give me the value of a I tell you value of a is four then can you tell me the

of a is four then can you tell me the value of a that will be four yes or no

value of a that will be four yes or no is this clear please tell me so remember

is this clear please tell me so remember this this type of functional dependenc

this this type of functional dependenc this is a functional dependency and this

this is a functional dependency and this functional dependency will always be

functional dependency will always be true in every instance of every relation

true in every instance of every relation yes or no this functional dependency

yes or no this functional dependency will always be true in every instance of

will always be true in every instance of every relation is this clear okay now

every relation is this clear okay now you tell me about this type of

you tell me about this type of functional dependency AB determining a

functional dependency AB determining a what about this type of functional

what about this type of functional dependency if I tell you the value of ab

dependency if I tell you the value of ab can you tell me the value of a please

can you tell me the value of a please tell me like let me give you let me give

tell me like let me give you let me give you given I'm giving you the value of ab

you given I'm giving you the value of ab I'm giving you the value of ab now can

I'm giving you the value of ab now can you give me the value of a Now find the

you give me the value of a Now find the value of a can you determine the value

value of a can you determine the value of a what will be the value of a please

of a what will be the value of a please tell me I'm giving you the value of a

tell me I'm giving you the value of a now can you determine the value of a yes

now can you determine the value of a yes you can determine the value of a will

you can determine the value of a will be yes we can determine and that value

be yes we can determine and that value of a that will be one is this clear so

of a that will be one is this clear so can you notice this is also trivially

can you notice this is also trivially true this will also hold again this will

true this will also hold again this will always

always hold again I can say this will always

hold again I can say this will always hold in every

hold in every instance in every instance of every

instance in every instance of every relation yes or no this will always hold

relation yes or no this will always hold in every instance of every

in every instance of every relation so this is Trivial this is also

relation so this is Trivial this is also trivial because this will always be true

trivial because this will always be true if I tell you the value of ab can you

if I tell you the value of ab can you find out the value of a if I tell you

find out the value of a if I tell you the value of ab is

the value of ab is 55 okay I'm telling you the value of ab

55 okay I'm telling you the value of ab that is 55 then what the value of a that

that is 55 then what the value of a that will be five yes or no so if I give you

will be five yes or no so if I give you the value of a can you determine the

the value of a can you determine the value of a yes you can do that so you

value of a yes you can do that so you can see this will always hold so this is

can see this will always hold so this is also trivial functional dependency okay

also trivial functional dependency okay so very simple point this is your

so very simple point this is your trivial functional dependency I can say

trivial functional dependency I can say this is the trivial functional

this is the trivial functional dependency now can you tell me what the

dependency now can you tell me what the definition of trivial functional

definition of trivial functional dependency similarly this is also your

dependency similarly this is also your Tri functional

Tri functional dependency this is also trivial

dependency this is also trivial functional dependency so can you tell me

functional dependency so can you tell me the definition of trivial functional

the definition of trivial functional dependency let me

dependency let me know what the definition of trivial

know what the definition of trivial functional dependency tell me what is

functional dependency tell me what is Trivial functional dependency trivial

Trivial functional dependency trivial functional dependency

functional dependency means X determines Y is a trivial

means X determines Y is a trivial functional dependency this is Trivial

functional dependency this is Trivial functional dependency if and only if

functional dependency if and only if this x is a superet of y this x is a

this x is a superet of y this x is a superet of Y is this clear okay this x

superet of Y is this clear okay this x is superet of Y for example here you can

is superet of Y for example here you can notice this AB this is a superet of a

notice this AB this is a superet of a yes or no this AB this is superet of a

yes or no this AB this is superet of a for example here you can notice this a

for example here you can notice this a this is superet of a so this is the

this is superet of a so this is the definition of trivial functional

definition of trivial functional dependency trivial functional dependency

dependency trivial functional dependency means X determines y this is Trivial

means X determines y this is Trivial functional dependency if and only if x

functional dependency if and only if x is superet of Y is this clear please

is superet of Y is this clear please tell me this is the idea X is of Y okay

tell me this is the idea X is of Y okay so this type of functional dependency

so this type of functional dependency this will be called a trivial functional

this will be called a trivial functional dependency okay and remember trivial

dependency okay and remember trivial functional dependency always

functional dependency always holds trivial functional dependency

holds trivial functional dependency always

always holds always

holds always holds in every

holds in every instance in every instance in every

instance in every instance in every instance of every relation is this point

instance of every relation is this point clear let me

clear let me know okay so very simple point that this

know okay so very simple point that this trivial functional dependency this will

trivial functional dependency this will always be true this will always be true

always be true this will always be true in every instance of every relation so

in every instance of every relation so this is the concept of trivial

this is the concept of trivial functional dependency now tell me when

functional dependency now tell me when can I say a functional dependency is

can I say a functional dependency is non-trivial when can I say a functional

non-trivial when can I say a functional dependency is non-trivial please tell me

dependency is non-trivial please tell me what the definition of non-trivial

what the definition of non-trivial functional dependency the name itself is

functional dependency the name itself is telling you non-trivial means which is

telling you non-trivial means which is not trivial yes or no FD which is not

not trivial yes or no FD which is not trivial FD which is not trivial which is

trivial FD which is not trivial which is not trivial the name itself is telling

not trivial the name itself is telling you non-trivial functional dependency

you non-trivial functional dependency means an FD okay a functional dependency

means an FD okay a functional dependency which is not trivial for example okay uh

which is not trivial for example okay uh so in simple words I can say when can I

so in simple words I can say when can I say x determines Y is non-trivial tell

say x determines Y is non-trivial tell me when can I say this is a nontrivial

me when can I say this is a nontrivial FD when can I say this is non-trivial FD

FD when can I say this is non-trivial FD tell

tell me let me know I can say this is

me let me know I can say this is non-trivial FD if and only if X is not

non-trivial FD if and only if X is not superet of Y yes or no if and only if X

superet of Y yes or no if and only if X is not superet of Y okay then this will

is not superet of Y okay then this will be called non-trivial functional depend

be called non-trivial functional depend uh non-trivial functional dependency is

uh non-trivial functional dependency is this clear very simple point so remember

this clear very simple point so remember if it is not trivial then it is

if it is not trivial then it is non-trivial is this clear let me ask you

non-trivial is this clear let me ask you some questions for example let's assume

some questions for example let's assume r a b c d okay this relation I'm giving

r a b c d okay this relation I'm giving you now you tell me which is

you now you tell me which is non-trivial which FD is non-trivial some

non-trivial which FD is non-trivial some functional dependencies I'm giving you

functional dependencies I'm giving you and you tell me which of them is

and you tell me which of them is non-trivial which functional dependency

non-trivial which functional dependency is non-trivial for example let me give

is non-trivial for example let me give you some questions like a determining a

you some questions like a determining a let me ask you another question a

let me ask you another question a determining

determining B AB determining

AC a determining BC

BC a determining

a Ab CD determining AB okay tell me which of them is Trivial

AB okay tell me which of them is Trivial which of them is not trivial let me know

which of them is not trivial let me know which of them is Trivial which of them

which of them is Trivial which of them is not trivial which functional

is not trivial which functional dependenc is not trivial so you can see

dependenc is not trivial so you can see this is Trivial right yes or no this is

this is Trivial right yes or no this is Trivial this is a trivial this is

Trivial this is a trivial this is Trivial right agree so you can see this

Trivial right agree so you can see this is

is Trivial what about this this is also

Trivial what about this this is also trivial this is also trivial okay you

trivial this is also trivial okay you can see which is non-trivial you can see

can see which is non-trivial you can see this is non-trivial because this is not

this is non-trivial because this is not superet of

superet of BC this is non-trivial because you can

BC this is non-trivial because you can see this a this a this is not superet of

see this a this a this is not superet of ab this is

ab this is non-trivial this is Trivial this is

non-trivial this is Trivial this is non-trivial this is non-trivial is this

non-trivial this is non-trivial is this clear so which functional dependencies

clear so which functional dependencies are non-trivial the answer will be 2 3 4

are non-trivial the answer will be 2 3 4 5 6 yes or no the answer will be 2 3 4 5

5 6 yes or no the answer will be 2 3 4 5 6 2 3 4 5 6 these are the non-trivial is

6 2 3 4 5 6 these are the non-trivial is this point clear please tell me so very

this point clear please tell me so very simple non-trivial functional dependency

simple non-trivial functional dependency means a functional dependency which is

means a functional dependency which is not trivial

not trivial okay so this is the definition of

okay so this is the definition of trivial and non-trivial so what the

trivial and non-trivial so what the definition of trivial Alpha implies beta

definition of trivial Alpha implies beta is Trivial if Alpha is superet of beta

is Trivial if Alpha is superet of beta Alpha is a superet of beta or I can say

Alpha is a superet of beta or I can say beta is a subset of alpha yes or no so

beta is a subset of alpha yes or no so Alpha implies beta that is Trivial if

Alpha implies beta that is Trivial if and only if beta is a subset of alpha or

and only if beta is a subset of alpha or I can say LHS is a superet of rhs yes or

I can say LHS is a superet of rhs yes or no LHS is superet of rhs remember if you

no LHS is superet of rhs remember if you have this functional dependency then

have this functional dependency then this Alpha this Alpha will be called LHS

this Alpha this Alpha will be called LHS and this beta will be called rhs is this

and this beta will be called rhs is this clear please tell me is this clear now

clear please tell me is this clear now tell me if I give you this functional

tell me if I give you this functional dependency if I give you this functional

dependency if I give you this functional dependency now tell me who is LHS who is

dependency now tell me who is LHS who is LHS if I give you this functional

LHS if I give you this functional dependency who is LHS remember this is

dependency who is LHS remember this is same as B determining a these are same

same as B determining a these are same so remember this B will be the LHS okay

so remember this B will be the LHS okay so here remember this is the LHS

so here remember this is the LHS and remember this a will be the

and remember this a will be the rhs okay so very simple point so

rhs okay so very simple point so remember whenever you have a functional

remember whenever you have a functional dependency Alpha implies beta then this

dependency Alpha implies beta then this Alpha will be LHS and beta will be rhs

Alpha will be LHS and beta will be rhs okay so very simple point so we have

okay so very simple point so we have seen what is a trivial functional

seen what is a trivial functional dependency trivial functional dependency

dependency trivial functional dependency means this is a subset of this I can say

means this is a subset of this I can say this rhs is subset of LHS yes or no rhs

this rhs is subset of LHS yes or no rhs is subset of LHS this is called trivial

is subset of LHS this is called trivial functional dependency otherwise if a

functional dependency otherwise if a functional dependency is not trivial

functional dependency is not trivial then it is non-trivial yes or no so you

then it is non-trivial yes or no so you can see so you can see this that if a

can see so you can see this that if a functional dependency is not trivial

functional dependency is not trivial okay otherwise it will be non-trivial

okay otherwise it will be non-trivial okay so either a functional independency

okay so either a functional independency will be trivial or it will be

will be trivial or it will be non-trivial very simple point now let me

non-trivial very simple point now let me tell you one more concept that is given

tell you one more concept that is given Inman book see this is not given in

Inman book see this is not given in other books only in the man book this is

other books only in the man book this is given that is something called compl

given that is something called compl completely non-trivial okay this concept

completely non-trivial okay this concept this concept is given in the ulman book

this concept is given in the ulman book this concept is given in the man book

this concept is given in the man book only this definition this is just a

only this definition this is just a definition nothing else okay this is

definition nothing else okay this is given in only in thean book this is not

given in only in thean book this is not given in the N this is not given in cour

given in the N this is not given in cour this is not given in I can say rurak

this is not given in I can say rurak Krishna but this is only given in the

Krishna but this is only given in the man but this is also very simple when

man but this is also very simple when can I say completely non-trivial

can I say completely non-trivial completely non-trivial that means LHS

completely non-trivial that means LHS and rhs they are disjointed completely

and rhs they are disjointed completely non-al what that means that means LHS

non-al what that means that means LHS and rhs they are disjointed means they

and rhs they are disjointed means they have nothing common they have nothing

have nothing common they have nothing common this will be called completely

common this will be called completely non-trivial okay so this is just a

non-trivial okay so this is just a definition nothing else so you can see

definition nothing else so you can see trivial means what trivial means trivial

trivial means what trivial means trivial means these B's these are subset of A's

means these B's these are subset of A's non-trivial means non-trivial means that

non-trivial means non-trivial means that it is not trivial okay non-trivial that

it is not trivial okay non-trivial that means it is not trivial and what is

means it is not trivial and what is completely non-trivial that means LHS

completely non-trivial that means LHS and rhs they have nothing

and rhs they have nothing common is this clear see what the

common is this clear see what the definition of trival please tell me if

definition of trival please tell me if if I give you a functional dependency X

if I give you a functional dependency X determining y when can I say it will be

determining y when can I say it will be trivial let me know when can I say it

trivial let me know when can I say it will be

will be trivial when can I say this is Trivial

trivial when can I say this is Trivial this will be trivial if this LHS is

this will be trivial if this LHS is superet of rhs okay very simple when can

superet of rhs okay very simple when can I say this is

I say this is non-trivial when can I say this is

non-trivial when can I say this is non-trivial when can I say this will be

non-trivial when can I say this will be non-trivial non-trivial means X is not

non-trivial non-trivial means X is not superet of Y yes or no simply in simple

superet of Y yes or no simply in simple words in simple words in simple words

words in simple words in simple words not

not trivial okay in simple words I can say

trivial okay in simple words I can say not trivial and when can I say it is

not trivial and when can I say it is completely

completely non-trivial when can I say it is

non-trivial when can I say it is completely

non-trivial when can I say that it is completely non-trivial when can I say

completely non-trivial when can I say that is completely non-al

that is completely non-al this we will say that when X

this we will say that when X intersection Y is empty when they have

intersection Y is empty when they have nothing common they have nothing common

nothing common they have nothing common X comma y are completely disjointed okay

X comma y are completely disjointed okay that means X comma y have nothing

that means X comma y have nothing common have nothing

common okay so their intersection is five in this situation we will call it

five in this situation we will call it completely non-trivial so these are the

completely non-trivial so these are the three definitions okay quite easy quite

three definitions okay quite easy quite easily you can see okay so very simple

easily you can see okay so very simple now let's move on now let's see this

now let's move on now let's see this question tell me the answer for this

question tell me the answer for this question what the answer for this

question what the answer for this question regarding trivial functional

question regarding trivial functional dependencies which best describes

dependencies which best describes completely non-trivial the question is

completely non-trivial the question is asking for the definition of completely

asking for the definition of completely non-trivial so what is the definition of

non-trivial so what is the definition of completely non-trivial if a functional

completely non-trivial if a functional dependency X to Y holds where X

dependency X to Y holds where X intersection Y is five yes this is the

intersection Y is five yes this is the definition of completely non-trivial yes

definition of completely non-trivial yes or no this is the definition of

or no this is the definition of completely non- trial tell me tell me

completely non- trial tell me tell me this is the definition of what this

this is the definition of what this statement this is statement if a

statement this is statement if a functional dependency holds where Y is

functional dependency holds where Y is subset of X this is your trivial

subset of X this is your trivial functional

functional dependency this is your trivial

dependency this is your trivial functional dependency what about this

functional dependency what about this last one what about this last one tell

last one what about this last one tell me this last one what about the last one

me this last one what about the last one the last one is

the last one is non-trivial the last one is non-trivial

non-trivial the last one is non-trivial this is non-trivial functional

this is non-trivial functional dependencies okay and this middle one

dependencies okay and this middle one what is this middle one this is your

what is this middle one this is your completely

non-trivial this is your completely non-trivial so can I say this is

non-trivial so can I say this is non-trivial also can I say every

non-trivial also can I say every completely non-trivial that is

completely non-trivial that is non-trivial every completely non-trivial

non-trivial every completely non-trivial is non-trivial also yes of course yes of

is non-trivial also yes of course yes of course right okay so remember this is

course right okay so remember this is non-trivial also this implies

non-trivial also this implies non-trivial also okay this implies

non-trivial also okay this implies non-trivial also okay so very simple

non-trivial also okay so very simple point so this is the definition of

point so this is the definition of trivial this is the definition of

trivial this is the definition of non-rival and this is the definition of

non-rival and this is the definition of completely non-trivial so this is the

completely non-trivial so this is the idea okay let's move on

idea okay let's move on now now I want to tell you one thing a

now now I want to tell you one thing a misconception I want to tell you maybe

misconception I want to tell you maybe some of you have seen this word

some of you have seen this word semi-trivial have you seen this

semi-trivial have you seen this word maybe you have seen this word on

word maybe you have seen this word on the YouTube or maybe in some other uh

the YouTube or maybe in some other uh know standard resources okay maybe you

know standard resources okay maybe you have seen

have seen this in some coaching Institute maybe

this in some coaching Institute maybe you have seen this so let me tell you

you have seen this so let me tell you this does not exist in the standard

this does not exist in the standard resources this semi-trivial no such

resources this semi-trivial no such concept exist in standard resources so

concept exist in standard resources so this is not a standard concept okay so

this is not a standard concept okay so anyway I'm just see some students are

anyway I'm just see some students are saying that uh they are reading dbms for

saying that uh they are reading dbms for the first time that is good okay that is

the first time that is good okay that is good whatever I'm teaching you I'm

good whatever I'm teaching you I'm telling you I'm teaching you from the

telling you I'm teaching you from the standard resources for every concept I'm

standard resources for every concept I'm giving you multiple I can say screenshot

giving you multiple I can say screenshot of standard resources ulman nagak

of standard resources ulman nagak Krishna okay all the standard resources

Krishna okay all the standard resources we are covering but I'm telling you that

we are covering but I'm telling you that in some in some coaching institutes this

in some in some coaching institutes this type of Concepts this type of concepts

type of Concepts this type of concepts are taught okay this semi-trivial

are taught okay this semi-trivial functional dependency this is taught but

functional dependency this is taught but let me tell you no such concept exist in

let me tell you no such concept exist in any standard resource there is no

any standard resource there is no standard resource containing this type

standard resource containing this type of concept okay so very simple Point

of concept okay so very simple Point okay this semi-trivial functional

okay this semi-trivial functional dependency this type of concept does not

dependency this type of concept does not exist in the standard resources okay so

exist in the standard resources okay so whatever we have seen that that is from

whatever we have seen that that is from the standard resources trivial

the standard resources trivial functional dependency non-trivial

functional dependency non-trivial functional dependency everything that we

functional dependency everything that we have seen okay is this clear let me

have seen okay is this clear let me know now one more topic one small topic

know now one more topic one small topic that is another notation for functional

that is another notation for functional dependencies this is another notation

dependencies this is another notation this is another way of uh I can say

this is another way of uh I can say describing the functional dependency

describing the functional dependency what is this another notation this is

what is this another notation this is just a notation nothing else remember

just a notation nothing else remember this is just a alternative notation for

this is just a alternative notation for functional dependency what this notation

functional dependency what this notation says this notation says that see if you

says this notation says that see if you have this functional dependency a

have this functional dependency a determines B then you can you can you

determines B then you can you can you can describe this like this see okay A B

can describe this like this see okay A B C D what you can do you can put like

C D what you can do you can put like this that a like this okay see very

this that a like this okay see very simple this is just a notation these two

simple this is just a notation these two things are same these two things are

things are same these two things are same for example if you want to describe

same for example if you want to describe a determines BC how will you do that if

a determines BC how will you do that if you want to describe a determines BC how

you want to describe a determines BC how will you do that this LHS this LHS you

will you do that this LHS this LHS you will do like this and for the rhs you

will do like this and for the rhs you will put the arrow okay for the rhs you

will put the arrow okay for the rhs you will put the arrow like this is this

will put the arrow like this is this clear this is just a notation this is

clear this is just a notation this is just an alternative notation nothing

just an alternative notation nothing else please tell me did you understand

else please tell me did you understand this this is just an alternative

this this is just an alternative notation that this functional dependency

notation that this functional dependency you can represent like this okay so what

you can represent like this okay so what is here see what is happening means

is here see what is happening means basically I'm saying that LHS implies

basically I'm saying that LHS implies rhs this you can this you can denote

rhs this you can this you can denote like this in LHS let's assume you have

like this in LHS let's assume you have for example in LHS let's assume you have

for example in LHS let's assume you have AB determining let's assume CD okay

AB determining let's assume CD okay let's assume you have AB determining CD

let's assume you have AB determining CD then how will you denote it then how

then how will you denote it then how will you represent it a b CDE e how will

will you represent it a b CDE e how will you represent it very simple this is

you represent it very simple this is your LHS right this is your LHS so for

your LHS right this is your LHS so for this LHS you will use without Arrow okay

this LHS you will use without Arrow okay you will use it without Arrow you will

you will use it without Arrow you will show it without Arrow okay you will show

show it without Arrow okay you will show it without Arrow you will be shown okay

it without Arrow you will be shown okay without Arrow show without Arrow what I

without Arrow show without Arrow what I can say I can say that show this without

can say I can say that show this without Arrow show without arrow in this

Arrow show without arrow in this notation in this alternative

notation in this alternative notation alternative notation okay so in

notation alternative notation okay so in this alternative notation this LHS will

this alternative notation this LHS will be shown without Arrow okay for the LHS

be shown without Arrow okay for the LHS you don't have to put the arrow and for

you don't have to put the arrow and for the rhs you will put the arrow okay show

the rhs you will put the arrow okay show with

with arrow show with

arrow show with arrow so this is the notation see what

arrow so this is the notation see what is what will happen this is how you will

is what will happen this is how you will do so this is how you will do okay so

do so this is how you will do okay so something like this or what you can do

something like this or what you can do something like this you can do that like

something like this you can do that like this and then you will put Arrow

this and then you will put Arrow here is this clear please tell me is

here is this clear please tell me is this understood let me know so like this

this understood let me know so like this you can denote so remember this you will

you can denote so remember this you will put without arrow and this you will put

put without arrow and this you will put with arrow is this understood okay so

with arrow is this understood okay so very

very simple for example let's see this if

simple for example let's see this if this diagram is given to you then what

this diagram is given to you then what are the functional dependencies if this

are the functional dependencies if this diagram is given to you then what are

diagram is given to you then what are the functional

the functional dependencies from this diagram what are

dependencies from this diagram what are the functional

dependencies functional dependencies in part A what are the functional

part A what are the functional dependencies for example look at this

dependencies for example look at this see this is without Arrow right yes or

see this is without Arrow right yes or no this is without Arrow correct this is

no this is without Arrow correct this is without Arrow so what that means this is

without Arrow so what that means this is without arrow and these are Arrow Arrow

without arrow and these are Arrow Arrow Arrow Arrow okay so what I can say I can

Arrow Arrow okay so what I can say I can say SSN determines these four things yes

say SSN determines these four things yes or no okay SSN determines these four

or no okay SSN determines these four things so remember what this will mean

things so remember what this will mean what this entire thing this entire thing

what this entire thing this entire thing what this means this entire thing look

what this means this entire thing look at this entire thing okay this entire

at this entire thing okay this entire thing what this means this means that

thing what this means this means that SSN determines this is LHS basically

SSN determines this is LHS basically basically this means LHS this means LHS

basically this means LHS this means LHS and these arrows these are rhs so I can

and these arrows these are rhs so I can say SSN implies e

say SSN implies e name okay e name comma B date birthday

name okay e name comma B date birthday birthday date comma

birthday date comma address and comma D number

address and comma D number okay so like this so this is your

okay so like this so this is your functional dependency is this clear let

functional dependency is this clear let me know very simple right yes or no so

me know very simple right yes or no so remember this without Arrow this is your

remember this without Arrow this is your LHS and this Arrow these are your rhs so

LHS and this Arrow these are your rhs so like this you can say okay so this is

like this you can say okay so this is how you can do so very simple so this

how you can do so very simple so this means SSN implies this SSN this implies

means SSN implies this SSN this implies these things okay what about this next

these things okay what about this next one what about this

one see what about this one look at this and tell me what about this one here you

and tell me what about this one here you can again notice this is without Arrow

can again notice this is without Arrow right this is your LHS there is no Arrow

right this is your LHS there is no Arrow okay these are not connected c c see

okay these are not connected c c see okay this is separate it's not connected

okay this is separate it's not connected is this clear these are separate okay

is this clear these are separate okay this look at this look at this this is

this look at this look at this this is separate so here you can see that what

separate so here you can see that what this will be this will be that D number

this will be this will be that D number I can say d number implies what D number

I can say d number implies what D number implies D

implies D name d name

name d name comma D manager name d manager s name uh

comma D manager name d manager s name uh SSN D manager

SSN D manager SSN okay so this is the meaning I hope

SSN okay so this is the meaning I hope you understood similarly can you do for

you understood similarly can you do for the next one for the next how many fds

the next one for the next how many fds are there in the second one in the

are there in the second one in the second one how many fds are there look

second one how many fds are there look at the second one there are total three

at the second one there are total three fds okay what is the first FD okay let's

fds okay what is the first FD okay let's look at this second one in this what is

look at this second one in this what is FD number one FD number one what is that

FD number one FD number one what is that that is your LHS is this LHS is

that is your LHS is this LHS is combination of SSN comma p number yes or

combination of SSN comma p number yes or no combination of this implies

no combination of this implies ours okay very simple what is your FD

ours okay very simple what is your FD number two what is your functional

number two what is your functional dependency two that is SSN implies e

dependency two that is SSN implies e name SSN implies

name SSN implies eame okay what is your FD number three

eame okay what is your FD number three what is your FD number three that is p

what is your FD number three that is p number implies that is p number implies

number implies that is p number implies P name comma P

P name comma P location okay so is this clear let me

location okay so is this clear let me know so you have three functional

know so you have three functional dependencies fd1 fd2 fd3 so this is your

dependencies fd1 fd2 fd3 so this is your alternative notation nothing else very

alternative notation nothing else very simple this is very simple okay so this

simple this is very simple okay so this is your diagram notation you can read

is your diagram notation you can read okay you can check

okay you can check it now tell me the answer for this one

it now tell me the answer for this one what are the functional

what are the functional dependencies in this you find functional

dependencies in this you find functional dependencies how many functional

dependencies how many functional dependencies are given in this in this

dependencies are given in this in this diagram how many functional dependencies

diagram how many functional dependencies are given find functional

are given find functional dependencies so tell me what are the

dependencies so tell me what are the functional dependencies given by this

functional dependencies given by this diagram so you can see this functional

diagram so you can see this functional dependency tell me what this functional

dependency tell me what this functional dependency let me know this functional

dependency let me know this functional dependency is AB

dependency is AB determining c d e FG yes or no a

determining c d e FG yes or no a determining CD F EFG this is your this

determining CD F EFG this is your this is your functional dependency what is

is your functional dependency what is this functional dependency this

this functional dependency this functional dependency this is your a

functional dependency this is your a determining D what is this functional

determining D what is this functional dependency this is your e determining G

dependency this is your e determining G okay and finally what is this functional

okay and finally what is this functional dependency this is your C determining

dependency this is your C determining B okay understood so this notation is

B okay understood so this notation is this notation clear please tell me this

this notation clear please tell me this notation is it

notation is it clear

clear okay so let's solve this question tell

okay so let's solve this question tell me the answer for this

me the answer for this question a very nice question to help

question a very nice question to help you understand what is functional

you understand what is functional dependency what the meaning of

dependency what the meaning of functional

functional dependency understand the meaning of

dependency understand the meaning of functional dependency so there is a

functional dependency so there is a relation apply application form you know

relation apply application form you know okay so like for example when you will

okay so like for example when you will apply for the colleges after the gate

apply for the colleges after the gate exam you will apply for the colleges

exam you will apply for the colleges counseling you will do the counseling

counseling you will do the counseling right okay so this is your apply now SSN

right okay so this is your apply now SSN means student student serial number okay

means student student serial number okay this is your student serial number this

this is your student serial number this is like AAR card number something like

is like AAR card number something like that okay this is your student serial

that okay this is your student serial number so I can say this is like your

number so I can say this is like your AAR card number so you can say this is

AAR card number so you can say this is your student serial number this is

your student serial number this is unique right okay so anyway so this is

unique right okay so anyway so this is your student serial number next this is

your student serial number next this is your college name what is the c name the

your college name what is the c name the C name this is your college

C name this is your college name this is your college name okay now

name this is your college name okay now the question is saying which Real World

the question is saying which Real World situation is captured by this functional

situation is captured by this functional dependency which Real World situation is

dependency which Real World situation is captured by this functional dependency

captured by this functional dependency this functional dependency is given to

this functional dependency is given to you now tell me which Real World

you now tell me which Real World situation is captured by this functional

situation is captured by this functional dependency tell me what this functional

dependency tell me what this functional dependency says when you say that

dependency says when you say that SSN college name this combination

SSN college name this combination determines date okay means if this

determines date okay means if this combination is same please understand if

combination is same please understand if this combination is same then date will

this combination is same then date will be same if if if this combination is

be same if if if this combination is same then date will be same what that

same then date will be same what that means what that means for example let's

means what that means for example let's assume you uh let's assume okay let me

assume you uh let's assume okay let me take moit okay for example moit is

take moit okay for example moit is applying okay let's moit is applying for

applying okay let's moit is applying for it Bombay okay college name is it Bombay

it Bombay okay college name is it Bombay okay moit applies for I Bombay now in I

okay moit applies for I Bombay now in I Bombay for multiple courses you can

Bombay for multiple courses you can apply yes yes or no you can apply for

apply yes yes or no you can apply for multiple courses agree with me okay for

multiple courses agree with me okay for multiple courses you can apply for

multiple courses you can apply for example let's measure you can see this

example let's measure you can see this is your measure that is given to you

is your measure that is given to you okay measure so for multiple courses you

okay measure so for multiple courses you can apply now what moit is doing for

can apply now what moit is doing for computer science also he applies okay

computer science also he applies okay for maybe I can say for artificial

for maybe I can say for artificial intelligence also he applies okay okay

intelligence also he applies okay okay maybe he also applies for I can say uh

maybe he also applies for I can say uh Compu CDs okay so in I Bombay I think

Compu CDs okay so in I Bombay I think there is no CDs that is in Bangalore

there is no CDs that is in Bangalore anyway so you can see M applies for it

anyway so you can see M applies for it Bombay now you tell me this combination

Bombay now you tell me this combination whenever this combination is same date

whenever this combination is same date must be same agree with me do you agree

must be same agree with me do you agree with me do you agree with me that

with me do you agree with me that whenever this combination is same if

whenever this combination is same if this combination is same this

this combination is same this combination is same so this date must be

combination is same so this date must be same this date this must be same so okay

same this date this must be same so okay so let me say like for example for

so let me say like for example for April okay so you can see something like

April okay so you can see something like this I hope you you understood so you

this I hope you you understood so you can see that so from here what I can say

can see that so from here what I can say from here what I can say I can say that

from here what I can say I can say that for a particular College a particular

for a particular College a particular student can apply in all the courses on

student can apply in all the courses on a fixed date yes or no means if you take

a fixed date yes or no means if you take a student you take and a college you

a student you take and a college you take if this combination you take a

take if this combination you take a student plus combination uh sorry

student plus combination uh sorry student plus College this combination

student plus College this combination you take now for this combination all

you take now for this combination all the application forms they must be

the application forms they must be submitted on the same date yes or no do

submitted on the same date yes or no do you agree with me yes or no so remember

you agree with me yes or no so remember if moit wants to apply for it Bombay

if moit wants to apply for it Bombay then he has to apply for all the courses

then he has to apply for all the courses he has to apply on the same date do you

he has to apply on the same date do you agree is this clear please tell me this

agree is this clear please tell me this is the meaning yes or no so I can say I

is the meaning yes or no so I can say I can say that every application form from

can say that every application form from a student see every application from a

a student see every application from a student from a student to a specific

student from a student to a specific College must be on the same date this is

College must be on the same date this is the answer answer is option D is this

the answer answer is option D is this clear let me know now can you give me a

clear let me know now can you give me a situation which you will violate option

situation which you will violate option ABC can you violate option

ABC can you violate option ABC let's try to violate option ABC see

ABC let's try to violate option ABC see option A saying a student can only apply

option A saying a student can only apply for one college nothing like that yes or

for one college nothing like that yes or no nothing like that you can apply for

no nothing like that you can apply for multiple colleges you can apply for

multiple colleges you can apply for multiple colleges for example moit can

multiple colleges for example moit can apply for moit can apply for ISC Bank

apply for moit can apply for ISC Bank also okay for ISC Bangalore for computer

also okay for ISC Bangalore for computer science he can apply okay on some on

science he can apply okay on some on some other date or maybe same date does

some other date or maybe same date does not matter okay on same date also you

not matter okay on same date also you can apply but the point is that same

can apply but the point is that same student can apply for different colleges

student can apply for different colleges yes or no is this clear let me

yes or no is this clear let me know so very simple point so I can say

know so very simple point so I can say option A that is gone option A is gone

option A that is gone option A is gone is this clear a student can only apply

is this clear a student can only apply for one college that is not correct what

for one college that is not correct what about this one a student can apply to

about this one a student can apply to each College only once is this true is

each College only once is this true is this true that a student can apply to

this true that a student can apply to each College only once no you can notice

each College only once no you can notice moit can apply for I Bombay three times

moit can apply for I Bombay three times but on the same date yes or no you can

but on the same date yes or no you can apply three times but on the same date

apply three times but on the same date the date must not change yes or no you

the date must not change yes or no you should not change the date so moit can

should not change the date so moit can apply for it Bombay three times four

apply for it Bombay three times four times any number of times

times any number of times but on the same date the date must be

but on the same date the date must be same okay because for this combination

same okay because for this combination the date must be same if this

the date must be same if this combination is same then this value must

combination is same then this value must be same so this is the idea I hope you

be same so this is the idea I hope you understood so option b that is also gone

understood so option b that is also gone okay now what about option C A student

okay now what about option C A student must apply for all colleges on the same

must apply for all colleges on the same date a student must apply for all

date a student must apply for all colleges on the same date that is also

colleges on the same date that is also not correct for ISC Bangalore you can

not correct for ISC Bangalore you can apply on 10th April for it Bombay you

apply on 10th April for it Bombay you can apply on 4th April yes or no so this

can apply on 4th April yes or no so this is the idea is this

is the idea is this clear okay now let me tell you actually

clear okay now let me tell you actually normally it happens that ISC forms will

normally it happens that ISC forms will come before it Bombay forms okay so

come before it Bombay forms okay so application form of ISC Bangalore that

application form of ISC Bangalore that will come before your gate result okay

will come before your gate result okay so before your gate result remember when

so before your gate result remember when your gate result will come before that I

your gate result will come before that I application forms will be out okay so

application forms will be out okay so anyway now let's move

anyway now let's move on let's see this tell me the answer for

on let's see this tell me the answer for this

question tell me the answer for this question consider relation a b CDE e

question consider relation a b CDE e with functional dependencies these are

with functional dependencies these are the functional dependencies that are

the functional dependencies that are given to you suppose that there are

given to you suppose that there are atmost three different values for a b

atmost three different values for a b and d there are atmost three different

and d there are atmost three different values for a b d what is the maximum

values for a b d what is the maximum number of different values for E okay

number of different values for E okay the question is saying maximum three

the question is saying maximum three different values you have for a maximum

different values you have for a maximum three different values for B maximum

three different values for B maximum three different values for D now the

three different values for D now the question is asking maximum how many

question is asking maximum how many different values e can have is this

different values e can have is this clear did you understand the question

clear did you understand the question that a can have maximum three different

that a can have maximum three different values B can have maximum three

values B can have maximum three different

different values and D can have maximum three

values and D can have maximum three different values now the question is

different values now the question is asking that how many Ma maximum

asking that how many Ma maximum different values e can have so let's see

different values e can have so let's see this these functional dependencies are

this these functional dependencies are already given to you okay so first you

already given to you okay so first you check for C how many maximum different

check for C how many maximum different values C can have tell me see very

values C can have tell me see very simple point this relation is given to

simple point this relation is given to you A B CDE e okay and this functional

you A B CDE e okay and this functional dependency is given to you a determining

dependency is given to you a determining C first you tell me how many maximum how

C first you tell me how many maximum how many different values C can have now

many different values C can have now this is my question maximum how many

this is my question maximum how many different values C can

different values C can have maximum how many different

have maximum how many different values C can have this attribute C can

values C can have this attribute C can have tell

have tell me maximum how many different values C

me maximum how many different values C can have tell me see very simple Point

can have tell me see very simple Point very simple point that notice this this

very simple point that notice this this functional dependency is given to you

functional dependency is given to you okay this functional dependenc is given

okay this functional dependenc is given to you this a b c this functional

to you this a b c this functional dependenc is given to you so what you

dependenc is given to you so what you can do

can do for different combinations you can you

for different combinations you can you can put different values yes or no I

can put different values yes or no I want maximum number of values for C what

want maximum number of values for C what I want please understand I want maximum

I want please understand I want maximum different values for C I want different

different values for C I want different different values for C remember what I

different values for C remember what I want I want different different values

want I want different different values for C okay now you tell me one thing

for C okay now you tell me one thing this functional dependency is given to

this functional dependency is given to you if I give if I give you two

you if I give if I give you two different

different combinations I am giving you two

combinations I am giving you two different combinations is it mandatory C

different combinations is it mandatory C must must be different is it mandatory C

must must be different is it mandatory C must be different please tell me is it

must be different please tell me is it mandatory C must be different C okay it

mandatory C must be different C okay it is not mandatory C may or may not be

is not mandatory C may or may not be different yes or no for different

different yes or no for different combinations for different combinations

combinations for different combinations this C can be same or this C can be

this C can be same or this C can be different okay these are different

different okay these are different combinations so this C can be same or

combinations so this C can be same or different yes or no this C can be same

different yes or no this C can be same or different but what I want see this C

or different but what I want see this C can be same or different but what I want

can be same or different but what I want tell me but what I want I want maximum

tell me but what I want I want maximum different values so what I will do I

different values so what I will do I want maximum different values okay

want maximum different values okay remember what I want I want maximum

remember what I want I want maximum different values for

different values for C okay so this is what I

C okay so this is what I want I want maximum different values

want I want maximum different values this is the important part so what I

this is the important part so what I will do I will make sure that c has

will do I will make sure that c has different values so for every

different values so for every combination I will put a different value

combination I will put a different value okay for this combination different

okay for this combination different value for this combination different

value for this combination different different value okay for this

different value okay for this combination for this combination

combination for this combination different value is this clear for every

different value is this clear for every different combination I will put a

different combination I will put a different value for this combination

different value for this combination different value and so on so tell me how

different value and so on so tell me how many different combinations of a comma B

many different combinations of a comma B are there okay and so on you can see and

are there okay and so on you can see and so on okay you can easily see how many

so on okay you can easily see how many different combinations for a comma B

different combinations for a comma B please tell me like this you can create

please tell me like this you can create combinations for a comma B A2 B2 A2 B3

combinations for a comma B A2 B2 A2 B3 then A3 B1 and so on right yes or no is

then A3 B1 and so on right yes or no is this clear so tell me how many different

this clear so tell me how many different combinations are there for ab this AB

combinations are there for ab this AB this has three into three different

this has three into three different combinations these many different

combinations these many different combinations are

combinations are possible clear yes or no that means nine

possible clear yes or no that means nine nine different combinations are possible

nine different combinations are possible because a has three values B has three

because a has three values B has three values this is already given to you in

values this is already given to you in the question that a has three different

the question that a has three different values maximum three different Valu

values maximum three different Valu values for a maximum three different

values for a maximum three different values for B so they have three

values for B so they have three different different values now I can

different different values now I can simply say so they have total nine

simply say so they have total nine different combinations yes or no total

different combinations yes or no total nine different combinations are there

nine different combinations are there for ABC ab so total for C how many

for ABC ab so total for C how many different values possible nine yes or no

different values possible nine yes or no so I can say maximum nine different

so I can say maximum nine different values

values possible nine different values

possible nine different values possible values possible for C

possible values possible for C okay for this C maximum nine different

okay for this C maximum nine different values are possible now the question is

values are possible now the question is asking for D now the question is asking

asking for D now the question is asking for D and remember this CD determines e

for D and remember this CD determines e uh CD determines e and the question is

uh CD determines e and the question is asking for E okay the question the

asking for E okay the question the question you can see the question is

question you can see the question is asking for

asking for E so tell

E so tell me what will the answer now you can

me what will the answer now you can easily see this CD determines e this

easily see this CD determines e this combination determines e

combination determines e now you can see this has nine different

now you can see this has nine different values yes or no this has nine different

values yes or no this has nine different values this has three different values

values this has three different values so how many different combinations are

so how many different combinations are possible so tell me how many different

possible so tell me how many different combinations are possible for CD how

combinations are possible for CD how many CD combinations are possible please

many CD combinations are possible please tell me so you can see 9 into 3 that

tell me so you can see 9 into 3 that will be 21 okay 9 into 3 that will be

will be 21 okay 9 into 3 that will be sorry that will be 27 27 different

sorry that will be 27 27 different combinations are possible yes or no

combinations are possible yes or no different CD combinations

different CD combinations possible CD combinations possible these

possible CD combinations possible these many different CD combinations are

many different CD combinations are possible so tell me how many e combin

possible so tell me how many e combin how many e values are possible how many

how many e values are possible how many e values are possible for every

e values are possible for every combination you give a different value

combination you give a different value for every combination you give a

for every combination you give a different value E1 E2 and so on okay for

different value E1 E2 and so on okay for every combination what you will do you

every combination what you will do you will give a different value so very

will give a different value so very simple so finally here answer will be

simple so finally here answer will be maximum 27 different values

possible okay so this is your answer so for this question the answer will be

for this question the answer will be 27 is this understood so this is another

27 is this understood so this is another very simple question but I hope you

very simple question but I hope you understood the concept of functional

understood the concept of functional dependency is this clear the concept of

dependency is this clear the concept of functional dependency is this clear

functional dependency is this clear please tell me everything that we have

please tell me everything that we have seen so far is that clear every concept

seen so far is that clear every concept did you understand what is functional

did you understand what is functional dependency what is Trivial functional

dependency what is Trivial functional dependency non-trivial functional

dependency non-trivial functional dependency functional dependency is

dependency functional dependency is defined for the schema functional

defined for the schema functional dependency is not defined on the

dependency is not defined on the instance okay remember if you say that

instance okay remember if you say that functional dependency is Satisfied by

functional dependency is Satisfied by the schema then it means all the

the schema then it means all the instances will satisfy functional

instances will satisfy functional dependency okay remember function

dependency okay remember function dependency or any Integrity constant

dependency or any Integrity constant they are defined on the

they are defined on the schema okay so very simple all the

schema okay so very simple all the concepts we have seen in the next

concepts we have seen in the next lecture we will study rules for

lecture we will study rules for functional

functional dependencies so this topic we will study

dependencies so this topic we will study in the next lecture okay thank you

in the next lecture okay thank you everyone

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