Registering Models

Registering models in settings.py

It is nice to not have to modify the code of applications to add a relation to categories. You can therefore do all the registering in settings.py. For example:

CATEGORIES_SETTINGS = {
    'FK_REGISTRY': {
        'app.AModel': 'category',
        'app.MyModel': (
            'primary_category',
            {'name': 'secondary_category', 'related_name': 'mymodel_sec_cat'}, )
    },
    'M2M_REGISTRY': {
        'app.BModel': 'categories',
        'app.MyModel': ('other_categories', 'more_categories', ),
    }
}

The FK_REGISTRY is a dictionary whose keys are the model to which to add the new field(s). The value is a string or tuple of strings or dictionaries specifying the necessary information for each field.

The M2M_REGISTRY is a dictionary whose keys are the model to which to add the new field(s). The value is a string or tuple of strings specifying the necessary information for each field.

Registering one Category field to model

The simplest way is to specify the name of the field, such as:

CATEGORIES_SETTINGS = {
    'FK_REGISTRY': {
        'app.AModel': 'category'
    }
}

This is equivalent to adding the following the AModel of app:

category = models.ForeignKey(Category)

If you want more control over the new field, you can use a dictionary and pass other ForeignKey options. The name key is required:

CATEGORIES_SETTINGS = {
    'FK_REGISTRY': {
        'app.AModel': {'name': 'category', 'related_name': 'amodel_cats'}
    }
}

This is equivalent to adding the following the AModel of app:

category = models.ForeignKey(Category, related_name='amodel_cats')

Registering two or more Category fields to a Model

When you want more than one relation to Category, all but one of the fields must specify a related_name to avoid conflicts, like so:

CATEGORIES_SETTINGS = {
    'FK_REGISTRY': {
        'app.MyModel': (
            'primary_category',
            {'name': 'secondary_category', 'related_name': 'mymodel_sec_cat'}, )
    },

Registering one or more Many-to-Many Category fields to a Model

CATEGORIES_SETTINGS = {
    'M2M_REGISTRY': {
        'app.AModel': 'categories',
        'app.MyModel': (
            {'name': 'other_categories', 'related_name': 'other_cats'},
            {'name': 'more_categories', 'related_name': 'more_cats'},
        ),
    }
}

Registering a many-to-one relationship

To create a many-to-one relationship (foreign key) between a model and Django Categories, you register your model with the register_fk function.

register_fk(model, field_name='category', extra_params={}])

Parameters:

• model – The Django Model to link to Django Categories
• field_name – Optional name for the field default: category
• extra_params – Optional dictionary of extra parameters passed to the ForeignKey class.

Example, in your models.py:

import categories
categories.register_fk(MyModel)

If you want more than one field on a model you have to have some extra arguments:

import categories
categories.register_fk(MyModel, 'primary_category')
categories.register_fk(MyModel, 'secondary_category', {'related_name':'mymodel_sec_cat'})

The extra_args allows you to specify the related_name of one of the fields so it doesn’t clash.

Registering a many-to-many relationship

To create a many-to-many relationship between a model and Django Categories, you register your model with the register_m2m function.

register_m2m(model, field_name='categories', extra_params={}])

Parameters:

• model – The Django Model to link to Django Categories
• field_name – Optional name for the field default: categories
• extra_params – Optional dictionary of extra parameters passed to the ManyToManyField class.

Example, in your models.py:

import categories
categories.register_m2m(MyModel)