In implementation terms when is an entity considered to be existence-dependent?

### If it has mandatory FKs. In other words, it has FKs that cannot be null.

## Step1: Understanding Entity Dependency### An entity is considered to be existence-dependent if its existence is contingent upon the existence of another entity. This is often represented through foreign keys (FKs) that link the entity to another entity.## Step2: Identifying Mandatory FKs### Mandatory FKs are those that cannot be null. This means that the value of the FK must be present for the record to be valid. If a FK is null, it implies that the entity does not have a corresponding record in the referenced entity, making the entity existence-dependent.## Step3: Relating FKs to Entity Existence### If an entity has mandatory FKs, it implies that the entity cannot exist without a corresponding record in the referenced entity. Therefore, the entity is considered to be existence-dependent.