6.17

Explain the difference between a weak and a strong entity set.

---

A weak entity set is one whose existence is dependent on another entity set, called its identifying entity set; instead of associating a primary key with a weak entity, we use the primary key of the identifying entity, along with extra attributes, called discriminator attributes to uniquely identify a weak entity.

An entity set that is not a weak entity set is termed a strong entity set.

Learn more in section 6.5.3 of the book.