GATE IT 2004 | Question: 73

Question

Consider the following entity relationship diagram $(ERD)$, where two entities $E1$ and $E2$ have a relation $R$ of cardinality 1:m.

The attributes of $E1$ are $A11$, $A12$ and $A13$ where $A11$ is the key attribute. The attributes of $E2$ are $A21$, $A22$ and $A23$ where $A21$ is the key attribute and $A23$ is a multi-valued attribute. Relation $R$ does not have any attribute. A relational database containing minimum number of tables with each table satisfying the requirements of the third normal form ($3NF$) is designed from the above $ERD$. The number of tables in the database is

• A. $2$
• B. $3$
• C. $5$
• D. $4$

Comments

And what will be the minimum number of tables required for this question, Will it be 2??

Answer 1

three tables one for E1  and one for E2 which will also include reationship R and 1 table for multivalued attribute of E2 whose PK wil be (21,23) together .hence 3 tables required.

Comments

Is it correct to say that every tuple in E1 corresponds to m in E2 or is it vice versa?

i am confused. plz clear me

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each tuple in E1 can be related to none(because E1 is partially participating in the relationship) or 1 or even more than one tuples of entity set E2…but each tuple in E2 will be related to at most 1 tuple in the E1 ….so u can say the it is one to many relationship ...with cardinality of E1 is m  and cardinality of E2 is 1.