Question

Given two relations:

Employee with structure as (ID, Name, Address, Phone, Deptno)
Department with structure as (Deptno, Dname)
__________ is used to represent the relationship between two relations Employee and Department.

• A. Primary key
• B. Alternate key
• C. Foreign key
• D. Candidate key

Hint:

Primary key = unique identifier in a table. Foreign key = reference to primary key in another table.

Answer 1

The Correct Option is C

Step 1: Recall the concept.
A foreign key is an attribute in one relation that refers to the primary key of another relation. It establishes a link between two tables.
Step 2: Apply to given relations.
- In the Department relation, Deptno is the primary key.
- In the Employee relation, Deptno appears as an attribute.
- Here, Employee(Deptno) acts as a foreign key referring to Department(Deptno).
Step 3: Eliminate wrong options.
- Primary key: Uniquely identifies tuples in the same table, not across two relations.
- Alternate key: Candidate key not chosen as primary key.
- Candidate key: Attributes that can act as a primary key.
Final Answer: \[ \boxed{\text{Foreign key is used to represent the relationship.}} \]