Number of Relations Required

Question

Soln. (My Solution)

.Lets Break it down shall we ?

Lets take an instance:-     

                  Dno          Dname          Phone            Office

                    1                 A                  X,Y                 Z,P

We know  Dno --> Phone,Office,Dname

Currently above one is not in 1nf so by converting it we get:- 

Dno            Dname           Phone          Office

 1                    A                    X                   Z

1                     A                     X                  P

1                     A                     Y                   Z

1                     A                      Y                   P

Now its in 1nf. But Now the Primary key is (Dno,Phone,Office) --->  Dname

but we know that Dno --> Dname

So its a Partial Dependency Hence not in 2nf

Lets Break it Down Further :----

A (Dno , Dname)     Dno as Primary Key

B (Dno,Phone,Office) and Primary key is (Dno,Phone,Office) collectively. So only two tables is required.

So is it a right statement :-  "If a relation has m number of multi-valued attribute then no need for m extra table only 1 table extra required like i just showed above" Ain't that right?

Is my solution Worth it ?

Comments

Yeah you are right, in RDBMS ,there shouldn't be any multivalued attribute,only allowed in ER diagram.

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So sir it means any number of multivalued attributes present in a relation can be dealt by making one extra table.

Thank u sir :)

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In this question only one entity is given ,if relation (two or more entities are related)is given then we have to check further .if only one entity is given like in this question then yes you are right.