1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
.. _topics-models:
======
Models
======
A model represents a single business logic or concept. It contains fields and
defines the behaviors of the record. Most of the time, each model stores record
in a single database table.
The basics:
* Each model is a Python class that subclasses one of
:class:`trytond.model.model.Model`.
* :ref:`Fields <ref-models-fields>` are defined as model attributes.
* Tryton generates the table definitions
* Tryton provides an API following the `active record pattern`_ to access the records.
.. _active record pattern: http://en.wikipedia.org/wiki/Active_record
Example
=======
This example defines a ``Party`` model which has a ``name`` and a ``code``
fields::
from trytond.model import ModelView, ModelSQL, fields
from trytond.pool import Pool
class Party(ModelSQL, ModelView):
"Party"
__name__ = "party.party"
name = fields.Char('Name')
code = fields.Char('Code')
Pool.register(Party)
The class must be registered in the :ref:`Pool <ref-pool>`.
Model classes are essentially data mappers to records and Model instances are
records.
Model attributes define meta-information of the model. They are class
attributes starting with an underscore. Some model properties are instance
attributes allowing to update them at other places in the framework.
|
