mirror of
https://github.com/django/django.git
synced 2024-12-23 17:46:27 +00:00
64 lines
1.5 KiB
Python
64 lines
1.5 KiB
Python
"""
|
|
Many-to-many relationships
|
|
|
|
To define a many-to-many relationship, use ``ManyToManyField()``.
|
|
|
|
In this example, an ``Article`` can be published in multiple ``Publication``
|
|
objects, and a ``Publication`` has multiple ``Article`` objects.
|
|
"""
|
|
from __future__ import unicode_literals
|
|
|
|
from django.db import models
|
|
from django.utils.encoding import python_2_unicode_compatible
|
|
|
|
|
|
@python_2_unicode_compatible
|
|
class Publication(models.Model):
|
|
title = models.CharField(max_length=30)
|
|
|
|
def __str__(self):
|
|
return self.title
|
|
|
|
class Meta:
|
|
ordering = ('title',)
|
|
|
|
|
|
@python_2_unicode_compatible
|
|
class Tag(models.Model):
|
|
id = models.BigAutoField(primary_key=True)
|
|
name = models.CharField(max_length=50)
|
|
|
|
def __str__(self):
|
|
return self.name
|
|
|
|
|
|
@python_2_unicode_compatible
|
|
class Article(models.Model):
|
|
headline = models.CharField(max_length=100)
|
|
# Assign a unicode string as name to make sure the intermediary model is
|
|
# correctly created. Refs #20207
|
|
publications = models.ManyToManyField(Publication, name='publications')
|
|
tags = models.ManyToManyField(Tag, related_name='tags')
|
|
|
|
def __str__(self):
|
|
return self.headline
|
|
|
|
class Meta:
|
|
ordering = ('headline',)
|
|
|
|
|
|
# Models to test correct related_name inheritance
|
|
class AbstractArticle(models.Model):
|
|
class Meta:
|
|
abstract = True
|
|
|
|
publications = models.ManyToManyField(Publication, name='publications', related_name='+')
|
|
|
|
|
|
class InheritedArticleA(AbstractArticle):
|
|
pass
|
|
|
|
|
|
class InheritedArticleB(AbstractArticle):
|
|
pass
|