Extending models

To extend an existing model, we use a Python class with an _inherit attribute, identifying the model to be extended. The new class inherits all the features of the parent Odoo model, and we only need to declare the modifications we want to introduce. These modifications will also be available everywhere else this model is used. We can think about this type of inheritance as getting a reference for the existing model and making in-place changes to it.

Adding fields to a model

We will extend the todo.task model to add some fields to it. As an example, we will now add the effort_estimate field, to be used for the amount of time expected to be spent on the task.

We will do this in a models/todo_task_model...