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[Music]
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thank you
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[Music]
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Hello friends welcome back to our
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channel so in the previous sessions we
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have discussed about the functional
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dependency and different properties of
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functional dependencies that Armstrong
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axioms and reference rules inference
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rules in this session we'll say One More
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Concept that is a types of functional
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dependencies
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thank you
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types of functional dependencies
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so coming to the first one so we'll take
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this table as an example so student
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table with a student ID student name age
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college and the place
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so coming to the first
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type
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so first one is in
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trivial
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trivial functional dependency
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so what is meant by this trivial
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functional dependency so in the previous
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session we have seen about the
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reflexivity
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reflexivity property of functional
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dependency the same will comes under
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this trivia that means if
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a tends to be
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is a functionally dependent
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then
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be
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is
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subset
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if B is subset of a then we call it as a
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trivial functional dependent okay so
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that means the dependent should be
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a subset of determinants so here A and B
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are the determinant and the dependent so
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a can be having a multiple attributes
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and B can have a multiple attributes so
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whatever the attributes are there in B
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should be a subset of a so such type of
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functional dependency is a trivial
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functional dependency so in this example
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consider here
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so
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trivial for trivial you can observe so
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the combination of S ID and s name
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can give S ID right
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so with the help of Sid and S name we
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can get Sid as a attribute so this is a
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self we can simply use this one okay so
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s name tends to s name is itself okay
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self functionally dependent because
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here these are called as a determinants
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and this is a dependent so by if you are
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having the Sid along the name we can
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have the Sid so which is nothing but a
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subset of this one which is nothing but
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a subset of this particular determinant
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so such type of dependency we call it as
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a trivial functional dependency trivial
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functional dependent
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so the second one is a non-trivial
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non-trivial functional dependent so
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quite opposite to this trivial so a
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tends to B is the functionality
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dependent if B is not a subset
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not a subset of a that means whatever
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the dependence we are having those
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should be not a subset of determinants
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okay so such type of functional
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dependency we call it as a non-trivial
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functional dependency so here coming
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with the example coming to this
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non-trivial so
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here you can get S ID comma s name
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can get age so age is functionally
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dependent on the combination of Sid and
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S name so you can observe here Sid and S
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name 101 Sunday gives it 25 1 0 2 sorry
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24 103 25 and 104 sorry 23 that means
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there is no redundancy here okay and we
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can get a edge also age or simply you
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can give age and college age and College
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right so here like this we can give
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which are not a subset of the
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determinants thus uh dependence should
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not be subset of determinants
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dependent set
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should not be
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subset
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of
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determinate
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so this is clear this is clear so on the
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left hand side which is a determinant on
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the right hand side is a dependent right
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so this type we call it as a non-trivial
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functional dependency
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and the third one
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multi-valued dependency
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multi-valued functional dependency
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so here
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a tends to BC is a functional dependent
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then
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B and C should not be independent should
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not be dependent that means
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either B tends to C or C tends to B
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should not be
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functionally dependent so then such type
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of thing we call it as a multi-value
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functional dependency such type of
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values we call it as a
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multi-valued dependency
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right
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so here
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multi-valued so simply here we can give
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S ID with the s name
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comma H so if if it is a so you can
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observe this is a functional dependency
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because with the help of Sid we can get
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both the s name and DH so there is no
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repetition simply we can get it now what
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we have to check means whether this
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functional dependency is a multi-valued
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or not that means so
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there should not be relation in between
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the dependents so
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no relation
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[Music]
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dependence
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dependence so here the dependent set is
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assignment ACH so consider s name
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tends to age
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or age
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tends to s name
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so these both are should not be
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dependent for first come to s name and
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age so Sandeep it's a 25 and sarada is
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24 and you can observe these two tooth
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pulls okay so we have seen the
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definition of functional dependencies so
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if you want to check for the functional
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dependency first we need to consider two
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tuples randomly so that if if two tuples
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are having the same x value that the
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same Tuple should have the corresponding
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y values also same right so here we are
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having the same X values are the so s
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name it's a survey but a different age
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24 23
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different age so this is not
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functionally dependent coming to the
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reverse process H tends to s name so 25
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year Sunday when 25 years satwik so this
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is also not possible so this is not a
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functionally dependent so that implies
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this particular functional dependency is
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multi-value functional dependency
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is a multi-value functional dependency
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right so hope you understood this one so
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one thing if a tends to BC is a
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functionally dependent then B and C
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should be dependent
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should not be dependent so
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should not be
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dependent right so that means B tends to
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C or C tends to be both should not be
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functionally dependent so here we have
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taken the example and we have translated
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right next one the fourth and the last
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one is a transitive functionally
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dependent so now also we have already
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observed in the Axiom property that is a
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transitivity rule right so the same
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thing here
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so the fourth one
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transitive
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functional dependency
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so a tends to B
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is a functionally dependent and B tends
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to C is also functionally dependent then
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a tends to C is functionally dependent
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so if a tends to B is functionally
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dependent and if B tends to C is
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functionally dependent similarly
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similarly so from these two functional
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dependencies we can derive a tends to c
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as a functional dependency so this is a
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type of situation we call it as a
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transitive functional dependencies so
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coming to the transitive
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transitive so here we can get S ID
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tends to college
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and College
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tends to place
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so simply we can say yes ID tends to
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place so let us check it let us check it
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first Sid
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tends to college we have to check
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whether it is a functional dependent or
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not so Sid and college so one zero one
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one zero two one zero three one zero
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four so there is no repetition so this
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is f d
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and coming to the college and place
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foreign
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college and place so I think
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yeah
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you can observe here also there is no
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repetition okay so BEC we are CC lbrc
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pvpa Sid so that means we are having a
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unique values different values there is
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no repetition
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right so you can observe here we for we
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are see we are set a college it's a
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place is Vijayawada and PVP societies
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for college places Vijayawada but we
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have to compare only if the X values are
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equal then we have to go with the Y
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values but here the X values are not
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equal so you need not bother about the Y
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values so this is also in a functionally
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dependent so what we have to do in the
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transitive functional dependency this
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implies yes idg
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determines the place that means
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if you have the student number we can
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say he is studying in which place so if
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you go with the sid101
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zero two it's a Vijayawada one zero
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three mileagram one zero four it's a
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Vijayawada so here also the X values are
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different so we need not bother about
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the Y values so this is the transitivity
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functional dependency transitive
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functional dependencies
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right so
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this is how these are the different
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types of functional dependencies
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available so once again I'll write the
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answer okay these are the examples so
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that you will be understanding clearly
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the first one
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trivial
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trivial
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non-trivial
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multi-value
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and
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transitive
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transitive so these are the different
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types of functional dependencies and
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once again I'm repeating so these are
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the base for the normalization because
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if you understand clearly about these
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functional dependencies that means what
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the functional dependency and what is
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the properties and the rules of
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functional dependencies and what are the
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different types of functional
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dependencies then it would be very easy
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to understand the normalization process
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right so if you are not aware about the
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functional dependency and the properties
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of functional dependency I'll post the
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playlist complete dbms play playlist
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Link in the description section so just
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to go through those two concepts while
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moving on towards normalization so sorry
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the three videos functional dependencies
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properties and types of functional
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dependencies so you just go through all
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these three so that the normalization
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process which we are going to explain in
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the next sessions will be easily
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understandable right so let's stop here
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and if you are having any doubts
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regarding these types of functional
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dependencies feel free to post your
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doubts in the comment section definitely
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I will try to clarify all your doubts
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and if you really enjoyed my session
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like my session share my session with
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your friends and don't forget to
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watching thank you very much