Let 𝐸1 and 𝐸2 be two entities in E-R diagram with simple single valued…
2015
Let 𝐸1 and 𝐸2 be two entities in E-R diagram with simple single valued attributes. 𝑅1 and 𝑅2 are two relationships between 𝐸1 and 𝐸2 where 𝑅1 is one-many and 𝑅2 is many-many. 𝑅1 and 𝑅2 do not have any attribute of their own. How many minimum number of tables are required to represent this situation in the Relational Model ?
- A.
4
- B.
3
- C.
2
- D.
1
Attempted by 577 students.
Show answer & explanation
Correct answer: B
Final answer: 3 tables.
Reasoning:
One table for entity E1 to store its simple attributes.
One table for entity E2 to store its simple attributes.
One junction table to represent the many-to-many relationship R2; it contains foreign keys referencing E1 and E2.
About the one-to-many relationship R1:
Since R1 has no attributes, it does not require a separate table. Implement R1 by adding a foreign key in the table for the entity on the many side that references the primary key of the one side.
Therefore, the minimum number of tables required is 3.
A video solution is available for this question — log in and enroll to watch it.