Data Modeling - Weak Entity

Question

Hello I’m studying about Data Modeling and I was left with doubt about the concept of Weak Entity.

I have already understood what is Weak Entity, which is an entity that needs keys from other entities in which they relate to then form its composite key.

However, in Professor Carlos Alberto Heuser’s book Data Modeling, he says that the concept 'weak entity' is not appropriate because this same entity may be relevant to another entity.

So, what should I consider about Weak Entity? In practice we use this concept?

Answer 1

If I understand correctly, the teacher gave a another vision of what is a weak entity.

We usually define whether an entity is weak or strong looking only to herself, but from what I understand the teacher understands that someone may be using the supposedly weak entity as the key, so she would no longer be weak. Makes sense to me.

In practice, as a developer, I have never modeled my tables under this concept and have never seen anyone (nor Dbas) use or quote this concept for such.