Question

For example if i have an Author class and a book class independently. We all know an author writes a book.

What i would love to know when it’s best to include the book as a reference object in the Author class or just include the book name?

The reason for this question ties mainly to flexibility and easy maintenance.

Update:

What design pattern should i read up that relate to this type of issue?

Answer 1

I would generally store the reference to the book, and the book object is therefore readily accessible from the author. If you store the property (name) in this scenario, then some questions are:

1. is the name unique ?
2. is it costly to retrieve the book from the author (e.g. do you have to go to the database) ?

If you don’t want the whole book object in memory (perhaps storing all authors with all their books consumes huge amounts of resource), then perhaps you want a book placeholder object referenced from the author class. That placeholder would store the book’s unique key and can retrieve the book upon demand. It may implement a book interface and thus be indistinguishable from the real book. The downside is that the book still has to be populated upon, or prior to, a request for info.