= Fixtures =

''It is very simple example, please, read something more complex if you need.'' 

Fixtures are very powerful to play with your database sample data during development process.
After each '''python manage.py reset <myapp>''' command you need to populate database with sample data again and again using admin interface. It's quite boring, isn't it?
With fixtures our life became more comfortable and easy. Look at this example.
Lets imagine that you have some data in db, so we can dump it. Even if your models have ForeignKeys or any kind of *To* relations.

First we need to define fixtures dir in settings file:

{{{
FIXTURE_DIRS = (
   '/path/to/myapp/fixtures/',
)
}}}

Lets dump our data:

{{{
cd /path/to/my_project
python manage.py dumpdata --format=json myapp > /path/to/myapp/fixtures/initial_data.json
}}}

Reset:

{{{
python manage.py reset myapp

You have requested a database reset.
This will IRREVERSIBLY DESTROY any data for
the "myapp" application in the database "mydb".
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: yes
}}}

Now we have clean DB, lets populate it with our sample data:

{{{
python manage.py syncdb
Loading 'initial_data' fixtures...
Installing json fixture 'initial_data' from '/path/to/myapp/fixtures/'.
Installed 24 object(s) from 1 fixture(s)
}}}

== Fixture loading ==

The location where Django loads a fixture from might seem unintuitive. As with template files the fixtures off all applications in a project share the same namespace. If you follow [source:django/trunk/django/core/management/commands/loaddata.py?rev=9770#L79 loaddata.py] you see that Django searches for {{{ *appnames*/fixtures }}} and {{{ settings.FIXTURE_DIRS }}}  and loads the first match. So if you use names like {{{ testdata.json }}} for your fixtures you must make sour that no other active application uses a fixture with the same name. If not, you can never be sure what fixtures you actually load.

Therefore it is suggested that you prefix your fixtures wit the application names, e.g. {{{ myapp/fixtures/myapp_testdata.json }}}.


Links:
[http://en.wikipedia.org/wiki/JSON]
[http://www.djangoproject.com/documentation/models/fixtures/]
[http://www.djangoproject.com/documentation/testing/#fixtures]