I'm currently learning about strong and weak entity types in the context of RDBMS. While reading, I came across this statement:
"A weak entity is dependent on a strong entity to ensure its existence. Unlike a strong entity, a weak entity does not have any primary key"
I'm starting to grasp the differences between strong and weak entity types and this statement seems incorrect to me. Specifically, it states that a weak entity does not have a primary key. However, shouldn't every entity possess a primary key? i.e., there MUST be combination of attributes that will provide uniqueness. So saying that a weak entity type does not have a primary key makes no sense.
However, it seems like the real definition of a weak entity type is an entity who's primary key MUST require a foreign key.
Is my definition of a weak entity correct?