hi.
i have 3 mysql tables:
---
a
id|name

b
id|name

a_b
a_id|b_id
---

i create 3 models:
Code:
Ext.define('a', {
    extend: 'Ext.data.Model',
    fields: ['id', 'name']
});
Ext.define('b', {
    extend: 'Ext.data.Model',
    fields: ['id', 'name']
});
Ext.define('a_b', {
    extend: 'Ext.data.Model',
    fields: ['a_id', 'b_id']
});
i need to get all "b" for model "a" defined in the model "a_b", and i need to get all "a" for model "b" defined in the model "a_b"

please help