Inheritance by Delegation - _inherits

Syntax ::

class tiny_object(osv.osv)
    _name = 'tiny.object'
    _table = 'tiny_object'
    _inherits = {
        'tiny.object_a': 'object_a_id',
        'tiny.object_b': 'object_b_id',
        ... ,
        'tiny.object_n': 'object_n_id'
    }
    (...)

The object ‘tiny.object’ inherits from all the columns and all the methods from the n objects ‘tiny.object_a’, ..., ‘tiny.object_n’.

To inherit from multiple tables, the technique consists in adding one column to the table tiny_object per inherited object. This column will store a foreign key (an id from another table). The values ‘object_a_id’ ‘object_b_id’ ... ‘object_n_id’ are of type string and determine the title of the columns in which the foreign keys from ‘tiny.object_a’, ..., ‘tiny.object_n’ are stored.

This inheritance mechanism is usually called ” instance inheritance ” or ” value inheritance “. A resource (instance) has the VALUES of its parents.