Delegation inheritance allows us to reuse data structures, without actually duplicating them in the database. This is done by embedding a Model inside another. UML terms this is a composition relationship: the child cannot exist without the parent, but the parent can exist without the child.
For example, for the core User Model, each record contains a Partner record, and so has all of the fields you find on a Partner available, plus a few fields that are specific to Users.
For the Library project, we want to add a Library Members Model. Members will be able to borrow books, and have a library card that can be used when borrowing books. We want to record the card number, and we also want to be ...
