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: Define the concept.
A foreign key is an attribute in one table that references the primary key of another table. It creates a connection between the two tables.
Step 2: Analyze the provided tables.
- The Department table has Deptno as its primary key.
- The Employee table contains the attribute Deptno.
- Thus, Employee's Deptno serves as a foreign key referencing Department's Deptno.
Step 3: Discard incorrect options.
- Primary key: Uniquely identifies rows within a single table, not between tables.
- Alternate key: A candidate key that was not selected as the primary key.
- Candidate key: Attributes capable of uniquely identifying rows, serving as potential primary keys.
Final Answer: \[\boxed{\text{Foreign key establishes the relationship between tables.}}\]