Question

What is a weak entity in an ER model?

• A. An entity that cannot exist without a related strong entity
• B. An entity that can have multiple relationships
• C. An entity without attributes
• D. An entity with a primary key

Hint:

A weak entity has no key of its own and relies on an owner strong entity to be identified.

Answer 1

The Correct Option is A

Step 1: A weak entity does not have a primary key of its own that can uniquely identify it.

Step 2: It depends on another entity, called the owner or strong entity, through an identifying relationship.

Step 3: Without that owner, the weak entity has no meaning and cannot exist in the database.

Step 4: So a weak entity cannot exist without a related strong entity. Answer is (A).