This is a simple addon to your models, with this package you can add metadata to any of your models.
By metadata we understand attributes/values that are not commonly shared across all instances of a particular model.
If you have a Product model and your instance is about Digital Cameras, you may want store what are it's resolution, storage capacity and lens type, but those informations have nothing to do with a lamp. These informations can easily be stored with django-metadata
Clone django-metadata somewhere:
git clone git://github.com/rafaelsdm/django-metadata.git
```
Add `django-metadata` into `PYTHONPATH`:
```bash
export PYTHONPATH=$PYTHONPATH:/somewhere/django-metadata
```
Remember to replace `/somewhere/` to the path where you cloned the code.
You can also add the line above into your `~/.bashrc`.
## Using
Import `metadata.models.MetaData` into your `model.py` file and create a `django.contrib.contenttypes.generic.GenericRelation` field where you want to use meta data
```python
# THIS IS JUST AN EXAMPLE
from django.db import models
from django.contrib.contenttypes import generic
from metadata.models import MetaData
class MyModel(models.Model):
foo = models.CharField(null=True, blank=True, max_length=1)
metadata = generic.GenericRelation(MetaData)
```
Add `metadata` into your `settings.INSTALLED_APPS`:
```python
# ...
INSTALLED_APPS = (
...
'metadata',
)
# ...
```
Now `manage.py syncdb` your project to create metadata models and have fun using it:
```python
from myapp.models import MyModel
mymodel = MyModel.objects.get(id=1)
mymodel.metadata['something'] = 'some value'
mymodel.metadata['something']
```
Note that `name` and `value` have a limit of 256 characteres, this is to increase performance and allow any database to index it ([PostgreSQL have limit](http://wiki.postgresql.org/wiki/FAQ#What_is_the_maximum_size_for_a_row.2C_a_table.2C_and_a_database.3F) on the size of a VARCHAR field to index it)
metadata manager objects are dict like objects, and implements `__setitem__`, `__getitem__`, `iterkeys`, `keys`, `itervalues`, `values`, `iteritems` and `items`, so you can use them at templates by doing some thing like:
```
{% if mymodel.metadata.something %}
```
So it will check if `mymodel` object has the metadata `something` into it
## Notes
This is not a replacement for fields into models, you should use it when some records have some data that other records (in the same table) have not.
As it's a very simple model with basic usage of GenericRelations and
Manager objects, it works pretty much with all 1.x versions of Django
(so far)