Question

Which relation is created with a composite primary key using the primary keys of the related entities and additional primary key attributes associated with the relationship or associative entity, plus any non-key attributes of the relationship or associative entity?

A) Binary 1:N relationship
B) Associative entity
C) Associative entity with its own key
D) Associative entity with additional key

Answer 1

The correct option is D. The relation described is an Associative Entity with additional key, used to manage many-to-many relationships between entities in a database, by incorporating the primary keys of the related entities along with additional attributes as composite keys.

Step-by-step explanation:

The relation described in the question is referred to as an Associative Entity with additional key. This construct is used in database design to manage a many-to-many relationship between two entities. The associative entity, sometimes called a join table or a linking table, has a composite primary key that specifically includes the primary keys of the related entities. Furthermore, it can incorporate additional attributes that are pertinent to the relationship, which can also serve as part of the composite primary key. In addition to the primary keys and any additional key attributes, the associative entity can contain non-key attributes that provide more detail about the associations or the relationship between the two entities.

For example, in a database for a bookstore, there can be an associative entity between the Authors and Books entities to represent which authors have written which books. If an author can co-write a book, the associative entity might be called Authorship, with a composite primary key consisting of the Author's ID, the Book's ID, and potentially additional attributes like the Role of the author, such as primary author or contributor.