More on using inheritance to extend models

We have seen the basic in place extension of models, which is also the most frequent use of inheritance. But inheritance using the _inherit attribute has more powerful capabilities, such as mixin classes.

We also have available the delegation inheritance method, using the _inherits attribute. It allows for a model to contain other models in a transparent way for the observer, while behind the scenes each model is handling its own data.

Let's explore these possibilities in more detail.

Copying features using prototype inheritance

The method we used before to extend a model used just the _inherit attribute. We defined a class inheriting the todo.task model, and added some features to it. The class attribute _name was not explicitly set; implicitly it was todo.task also.

But using the _name attribute allows us to create mixin classes, by setting it to the model we want to extend. Here is an example:

from openerp import models
class TodoTask(models...