Adding relational fields to a Model

Relations between Odoo Models are represented by relational fields. We can have three different types of relations: many-to-one, one-to-many, and many-to-many. Looking at the Library Books example, we see that each book can have one Publisher, so we can have a many-to-one relation between books and publishers.

Looking at it from the Publishers point of view, each Publisher can have many Books. So, the previous many-to-one relation implies a one-to-many reverse relation.

Finally, there are cases where we can have a many-to-many relation. In our example, each book can have several (many) Authors. And inversely, each Author can have written many books. Looking at it from either side, this is a many-to-many relation.

Getting ready

We will reuse the my_module addon module from Chapter 3, Creating Odoo Modules.

How to do it…

Odoo uses the Partner model, res.partner, to represent persons, organizations, and addresses. So, we should use it for authors and publishers...