If your plugin introduces a new type of object in NetBox, you'll probably want to create a [Django model](https://docs.djangoproject.com/en/stable/topics/db/models/) for it. A model is essentially a Python representation of a database table, with attributes that represent individual columns. Model instances can be created, manipulated, and deleted using [queries](https://docs.djangoproject.com/en/stable/topics/db/queries/). Models must be defined within a file named `models.py`.
Below is an example `models.py` file containing a model with two character fields:
```python
from django.db import models
class Animal(models.Model):
name = models.CharField(max_length=50)
sound = models.CharField(max_length=50)
def __str__(self):
return self.name
```
### Migrations
Once you have defined the model(s) for your plugin, you'll need to create the database schema migrations. A migration file is essentially a set of instructions for manipulating the PostgreSQL database to support your new model, or to alter existing models. Creating migrations can usually be done automatically using Django's `makemigrations` management command.
!!! note
A plugin must be installed before it can be used with Django management commands. If you skipped this step above, run `python setup.py develop` from the plugin's root directory.
Next, we can apply the migration to the database with the `migrate` command:
```no-highlight
$ ./manage.py migrate netbox_animal_sounds
Operations to perform:
Apply all migrations: netbox_animal_sounds
Running migrations:
Applying netbox_animal_sounds.0001_initial... OK
```
For more background on schema migrations, see the [Django documentation](https://docs.djangoproject.com/en/stable/topics/migrations/).
## Enabling NetBox Features
Plugin models can leverage certain NetBox features by inheriting from NetBox's `BaseModel` class. This class extends the plugin model to enable numerous feature, including:
If you prefer instead to enable only a subset of these features for a plugin model, NetBox provides a discrete "mix-in" class for each feature. You can subclass each of these individually when defining your model. (You will also need to inherit from Django's built-in `Model` class.)
from netbox.models.features import ExportTemplatesMixin, TagsMixin
class MyModel(ExportTemplatesMixin, TagsMixin, models.Model):
foo = models.CharField()
...
```
The example above will enable export templates and tags, but no other NetBox features. A complete list of available feature mixins is included below. (Inheriting all the available mixins is essentially the same as subclassing `BaseModel`.)
## Feature Mixins Reference
!!! note
Please note that only the classes which appear in this documentation are currently supported. Although other classes may be present within the `features` module, they are not yet supported for use by plugins.
