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Fixed #3098 -- Added db_table parameter to m2m fields, allowing the s…

…pecification of a custom table name for the m2m table. Thanks, Wolfram Kriesing.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4429 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit 54feaca70f77b39093fe417dcd89eb7c74930e2e 1 parent 12ad69c
@freakboy3742 freakboy3742 authored
View
6 django/db/models/fields/related.py
@@ -629,6 +629,7 @@ def __init__(self, to, **kwargs):
limit_choices_to=kwargs.pop('limit_choices_to', None),
raw_id_admin=kwargs.pop('raw_id_admin', False),
symmetrical=kwargs.pop('symmetrical', True))
+ self.db_table = kwargs.pop('db_table', None)
if kwargs["rel"].raw_id_admin:
kwargs.setdefault("validator_list", []).append(self.isValidIDList)
Field.__init__(self, **kwargs)
@@ -651,7 +652,10 @@ def get_choices_default(self):
def _get_m2m_db_table(self, opts):
"Function that can be curried to provide the m2m table name for this relation"
- return '%s_%s' % (opts.db_table, self.name)
+ if self.db_table:
+ return self.db_table
+ else:
+ return '%s_%s' % (opts.db_table, self.name)
def _get_m2m_column_name(self, related):
"Function that can be curried to provide the source column name for the m2m table"
View
4 docs/model-api.txt
@@ -874,6 +874,10 @@ the relationship should work. All are optional:
force Django to add the descriptor for the reverse
relationship, allowing ``ManyToMany`` relationships to be
non-symmetrical.
+
+ ``db_table`` The name of the table to create for storing the many-to-many
+ data. If this is not provided, Django will assume a default
+ name based upon the names of the two tables being joined.
======================= ============================================================
View
92 tests/modeltests/custom_columns/models.py
@@ -1,53 +1,105 @@
"""
-17. Custom column names
+17. Custom column/table names
If your database column name is different than your model attribute, use the
``db_column`` parameter. Note that you'll use the field's name, not its column
name, in API usage.
+
+If your database table name is different than your model name, use the
+``db_table`` Meta attribute. This has no effect on the API used to
+query the database.
+
+If you need to use a table name for a many-to-many relationship that differs
+from the default generated name, use the ``db_table`` parameter on the
+ManyToMany field. This has no effect on the API for querying the database.
+
"""
from django.db import models
-class Person(models.Model):
+class Author(models.Model):
first_name = models.CharField(maxlength=30, db_column='firstname')
last_name = models.CharField(maxlength=30, db_column='last')
def __str__(self):
return '%s %s' % (self.first_name, self.last_name)
+ class Meta:
+ db_table = 'my_author_table'
+ ordering = ('last_name','first_name')
+
+class Article(models.Model):
+ headline = models.CharField(maxlength=100)
+ authors = models.ManyToManyField(Author, db_table='my_m2m_table')
+
+ def __str__(self):
+ return self.headline
+
+ class Meta:
+ ordering = ('headline',)
+
__test__ = {'API_TESTS':"""
-# Create a Person.
->>> p = Person(first_name='John', last_name='Smith')
->>> p.save()
+# Create a Author.
+>>> a = Author(first_name='John', last_name='Smith')
+>>> a.save()
->>> p.id
+>>> a.id
1
->>> Person.objects.all()
-[<Person: John Smith>]
+# Create another author
+>>> a2 = Author(first_name='Peter', last_name='Jones')
+>>> a2.save()
+
+# Create an article
+>>> art = Article(headline='Django lets you build web apps easily')
+>>> art.save()
+>>> art.authors = [a, a2]
->>> Person.objects.filter(first_name__exact='John')
-[<Person: John Smith>]
+# Although the table and column names on Author have been set to
+# custom values, nothing about using the Author model has changed...
->>> Person.objects.get(first_name__exact='John')
-<Person: John Smith>
+# Query the available authors
+>>> Author.objects.all()
+[<Author: Peter Jones>, <Author: John Smith>]
->>> Person.objects.filter(firstname__exact='John')
+>>> Author.objects.filter(first_name__exact='John')
+[<Author: John Smith>]
+
+>>> Author.objects.get(first_name__exact='John')
+<Author: John Smith>
+
+>>> Author.objects.filter(firstname__exact='John')
Traceback (most recent call last):
...
TypeError: Cannot resolve keyword 'firstname' into field
->>> p = Person.objects.get(last_name__exact='Smith')
->>> p.first_name
+>>> a = Author.objects.get(last_name__exact='Smith')
+>>> a.first_name
'John'
->>> p.last_name
+>>> a.last_name
'Smith'
->>> p.firstname
+>>> a.firstname
Traceback (most recent call last):
...
-AttributeError: 'Person' object has no attribute 'firstname'
->>> p.last
+AttributeError: 'Author' object has no attribute 'firstname'
+>>> a.last
Traceback (most recent call last):
...
-AttributeError: 'Person' object has no attribute 'last'
+AttributeError: 'Author' object has no attribute 'last'
+
+# Although the Article table uses a custom m2m table,
+# nothing about using the m2m relationship has changed...
+
+# Get all the authors for an article
+>>> art.authors.all()
+[<Author: Peter Jones>, <Author: John Smith>]
+
+# Get the articles for an author
+>>> a.article_set.all()
+[<Article: Django lets you build web apps easily>]
+
+# Query the authors across the m2m relation
+>>> art.authors.filter(last_name='Jones')
+[<Author: Peter Jones>]
+
"""}
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