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Code Issues 32 Releases Wiki Activity

magic-removal: Implemented 'remove()' for m2m relationships, and tidied up related 'add()' code a bit

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git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2284 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Luke Plant 2006-02-06 21:02:33 +00:00
parent 1969c9f88b
commit a91ebaa2c3
1 changed files with 43 additions and 5 deletions
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48
django/db/models/fields/related.py
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@ -90,7 +90,7 @@ class SingleRelatedObjectDescriptor(object):
setattr(instance, cache_name, rel_obj) setattr(instance, cache_name, rel_obj)
return rel_obj return rel_obj
def do_m2m_add(rel_manager_inst, managerclass, rel_model, join_table, this_col_name, def _add_m2m_items(rel_manager_inst, managerclass, rel_model, join_table, this_col_name,
rel_col_name, this_pk_val, *objs, **kwargs): rel_col_name, this_pk_val, *objs, **kwargs):
# Utility function used by the ManyRelatedObjectsDescriptors # Utility function used by the ManyRelatedObjectsDescriptors
# to do addition to a many-to-many field. # to do addition to a many-to-many field.
@ -104,6 +104,7 @@ def do_m2m_add(rel_manager_inst, managerclass, rel_model, join_table, this_col_n
# *objs - objects to add, or **kwargs to create new objects # *objs - objects to add, or **kwargs to create new objects
from django.db import connection from django.db import connection
rel_opts = rel_model._meta
# Create the related object. # Create the related object.
if kwargs: if kwargs:
assert len(objs) == 0, "add() can't be passed both positional and keyword arguments" assert len(objs) == 0, "add() can't be passed both positional and keyword arguments"
@ -113,14 +114,38 @@ def do_m2m_add(rel_manager_inst, managerclass, rel_model, join_table, this_col_n
for obj in objs: for obj in objs:
if not isinstance(obj, rel_model): if not isinstance(obj, rel_model):
raise ValueError, "positional arguments to add() must be %s instances" % rel_opts.object_name raise ValueError, "positional arguments to add() must be %s instances" % rel_opts.object_name
# Add the newly created object to the join table. # Add the newly created or already existing objects to the join table.
# TODO: Check to make sure the object isn't already in the join table. # TODO: Check to make sure the object isn't already in the join table.
cursor = connection.cursor() cursor = connection.cursor()
for obj in objs: for obj in objs:
cursor.execute("INSERT INTO %s (%s, %s) VALUES (%%s, %%s)" % \ cursor.execute("INSERT INTO %s (%s, %s) VALUES (%%s, %%s)" % \
(join_table, this_col_name, rel_col_name), (join_table, this_col_name, rel_col_name),
[this_pk_val, obj._get_pk_val()]) [this_pk_val, obj._get_pk_val()])
connection.commit() connection.commit()
def _remove_m2m_items(rel_model, join_table, this_col_name,
rel_col_name, this_pk_val, *objs):
# Utility function used by the ManyRelatedObjectsDescriptors
# to do removal from a many-to-many field.
# rel_model: the model class of the 'related' object
# join_table: name of the m2m link table
# this_col_name: the PK colname in join_table for 'this' object
# rel_col_name: the PK colname in join_table for the related object
# this_pk_val: the primary key for 'this' object
# *objs - objects to remove
from django.db import connection
rel_opts = rel_model._meta
for obj in objs:
if not isinstance(obj, rel_model):
raise ValueError, "objects to remove() must be %s instances" % rel_opts.object_name
# Remove the specified objects from the join table
cursor = connection.cursor()
for obj in objs:
cursor.execute("DELETE FROM %s WHERE %s = %%s AND %s = %%s" % \
(join_table, this_col_name, rel_col_name),
[this_pk_val, obj._get_pk_val()])
connection.commit()
class ManyRelatedObjectsDescriptor(object): class ManyRelatedObjectsDescriptor(object):
# This class provides the functionality that makes the related-object # This class provides the functionality that makes the related-object
@ -162,9 +187,17 @@ class ManyRelatedObjectsDescriptor(object):
return superclass.add(self, **kwargs) return superclass.add(self, **kwargs)
else: else:
def add(self, *objs, **kwargs): def add(self, *objs, **kwargs):
do_m2m_add(self, superclass, rel_model, join_table, this_col_name, _add_m2m_items(self, superclass, rel_model, join_table, this_col_name,
rel_col_name, instance._get_pk_val(), *objs, **kwargs) rel_col_name, instance._get_pk_val(), *objs, **kwargs)
add.alters_data = True add.alters_data = True
if rel_type == "o2m":
def remove(self, *objs):
pass # TODO
else:
def remove(self, *objs):
_remove_m2m_items(rel_model, join_table, this_col_name,
rel_col_name, instance._get_pk_val(), *objs)
remove.alters_data = True
manager = RelatedManager() manager = RelatedManager()
@ -215,9 +248,14 @@ class ReverseManyRelatedObjectsDescriptor(object):
params = [instance._get_pk_val()] params = [instance._get_pk_val()]
) )
def add(self, *objs, **kwargs): def add(self, *objs, **kwargs):
do_m2m_add(self, superclass, rel_model, join_table, this_col_name, _add_m2m_items(self, superclass, rel_model, join_table, this_col_name,
rel_col_name, instance._get_pk_val(), *objs, **kwargs) rel_col_name, instance._get_pk_val(), *objs, **kwargs)
add.alters_data = True add.alters_data = True
def remove(self, *objs):
_remove_m2m_items(rel_model, join_table, this_col_name,
rel_col_name, instance._get_pk_val(), *objs)
remove.alters_data = True
manager = RelatedManager() manager = RelatedManager()
manager.model = self.rel_model manager.model = self.rel_model