Question

Weak entities must have full participation from the weak entity to the strong entity, but not necessary from the strong to the weak entity.

- true
- false

Answer 1

The claim is true; weak entities must have full participation with the strong entity to ensure uniqueness, but the strong entity does not need full participation with the weak entity as it has its own unique identifier and exists independently.

Step-by-step explanation:

The statement that weak entities must have full participation from the weak entity to the strong entity, but not necessarily from the strong to the weak entity is true. In a relational database model, a weak entity cannot be uniquely identified by its own attributes alone and relies on a foreign key in combination with its attributes to create a primary key, often referred to as a composite key. This dependence necessitates that every instance of a weak entity be associated with an instance of a strong entity, leading to full participation (total participation).

However, the reverse does not necessarily hold; a strong entity does not require full participation with the weak entity. In other words, not every instance of a strong entity is required to be linked to an instance of a weak entity. The strong entity exists independently and has its own unique identifier, making it optional for the strong entity to participate in the relationship.

Answer 2

False. In a relational database, weak entities are entities that do not have a primary key attribute of their own and rely on the existence of a related strong entity.