Difference between Strong and Weak Entity
Strong Entity | Weak Entity |
---|---|
Strong entity always has a primary key. | While a weak entity has a partial discriminator key. |
Strong entity is not dependent on any other entity. | Weak entity depends on strong entity. |
Strong entity is represented by a single rectangle. | Weak entity is represented by a double rectangle. |
Two strong entity’s relationship is represented by a single diamond. | While the relation between one strong and one weak entity is represented by a double diamond. |
Strong entities have either total participation or partial participation. | A weak entity has a total participation constraint. |
Difference between Strong and Weak Entity
Prerequisite – ER Model
An entity is a “thing” or “object” in the real world. An entity contains attributes, which describe that entity. So anything about which we store information is called an entity. Entities are recorded in the database and must be distinguishable, i.e., easily recognized from the group. In this article we will see difference between strong and weak entity.