Index: django/db/models/base.py =================================================================== --- django/db/models/base.py (revision 2304) +++ django/db/models/base.py (working copy) @@ -3,7 +3,7 @@ from django.db.models.fields import AutoField, ImageField from django.db.models.fields.related import OneToOne, ManyToOne from django.db.models.related import RelatedObject -from django.db.models.query import orderlist2sql +from django.db.models.query import orderlist2sql, delete_objects from django.db.models.options import Options, AdminOptions from django.db import connection, backend from django.db.models import signals @@ -49,15 +49,6 @@ register_models(new_class._meta.app_label, new_class) return new_class -def cmp_cls(x, y): - for field in x._meta.fields: - if field.rel and not field.null and field.rel.to == y: - return -1 - for field in y._meta.fields: - if field.rel and not field.null and field.rel.to == x: - return 1 - return 0 - class Model(object): __metaclass__ = ModelBase @@ -187,7 +178,7 @@ save.alters_data = True - def __collect_sub_objects(self, seen_objs): + def _collect_sub_objects(self, seen_objs): """ Recursively populates seen_objs with all objects related to this object. When done, seen_objs will be in the format: @@ -207,56 +198,21 @@ except ObjectDoesNotExist: pass else: - sub_obj.__collect_sub_objects(seen_objs) + sub_obj._collect_sub_objects(seen_objs) else: for sub_obj in getattr(self, rel_opts_name).all(): - sub_obj.__collect_sub_objects(seen_objs) + sub_obj._collect_sub_objects(seen_objs) def delete(self): assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname) + + # Find all the objects than need to be deleted seen_objs = {} - self.__collect_sub_objects(seen_objs) - - seen_classes = set(seen_objs.keys()) - ordered_classes = list(seen_classes) - ordered_classes.sort(cmp_cls) - - cursor = connection.cursor() - - for cls in ordered_classes: - seen_objs[cls] = seen_objs[cls].items() - seen_objs[cls].sort() - for pk_val, instance in seen_objs[cls]: - dispatcher.send(signal=signals.pre_delete, sender=cls, instance=instance) - - for related in cls._meta.get_all_related_many_to_many_objects(): - cursor.execute("DELETE FROM %s WHERE %s=%%s" % \ - (backend.quote_name(related.field.get_m2m_db_table(related.opts)), - backend.quote_name(cls._meta.object_name.lower() + '_id')), - [pk_val]) - for f in cls._meta.many_to_many: - cursor.execute("DELETE FROM %s WHERE %s=%%s" % \ - (backend.quote_name(f.get_m2m_db_table(cls._meta)), - backend.quote_name(cls._meta.object_name.lower() + '_id')), - [pk_val]) - for field in cls._meta.fields: - if field.rel and field.null and field.rel.to in seen_classes: - cursor.execute("UPDATE %s SET %s=NULL WHERE %s=%%s" % \ - (backend.quote_name(cls._meta.db_table), backend.quote_name(field.column), - backend.quote_name(cls._meta.pk.column)), [pk_val]) - setattr(instance, field.attname, None) - - for cls in ordered_classes: - seen_objs[cls].reverse() - for pk_val, instance in seen_objs[cls]: - cursor.execute("DELETE FROM %s WHERE %s=%%s" % \ - (backend.quote_name(cls._meta.db_table), backend.quote_name(cls._meta.pk.column)), - [pk_val]) - setattr(instance, cls._meta.pk.attname, None) - dispatcher.send(signal=signals.post_delete, sender=cls, instance=instance) - - connection.commit() - + self._collect_sub_objects(seen_objs) + + # Actually delete the objects + delete_objects(seen_objs) + delete.alters_data = True def _get_FIELD_display(self, field): Index: django/db/models/manager.py =================================================================== --- django/db/models/manager.py (revision 2304) +++ django/db/models/manager.py (working copy) @@ -57,9 +57,6 @@ def dates(self, *args, **kwargs): return self.get_query_set().dates(*args, **kwargs) - def delete(self, *args, **kwargs): - return self.get_query_set().delete(*args, **kwargs) - def distinct(self, *args, **kwargs): return self.get_query_set().distinct(*args, **kwargs) Index: django/db/models/query.py =================================================================== --- django/db/models/query.py (revision 2304) +++ django/db/models/query.py (working copy) @@ -1,6 +1,9 @@ from django.db import backend, connection from django.db.models.fields import DateField, FieldDoesNotExist +from django.db.models import signals +from django.dispatch import dispatcher from django.utils.datastructures import SortedDict + import operator LOOKUP_SEPARATOR = '__' @@ -125,7 +128,7 @@ extra_select = self._select.items() cursor = connection.cursor() - select, sql, params = self._get_sql_clause(True) + select, sql, params = self._get_sql_clause() cursor.execute("SELECT " + (self._distinct and "DISTINCT " or "") + ",".join(select) + sql, params) fill_cache = self._select_related index_end = len(self.model._meta.fields) @@ -149,7 +152,7 @@ counter._offset = None counter._limit = None counter._select_related = False - select, sql, params = counter._get_sql_clause(True) + select, sql, params = counter._get_sql_clause() cursor = connection.cursor() cursor.execute("SELECT COUNT(*)" + sql, params) return cursor.fetchone()[0] @@ -171,34 +174,31 @@ assert bool(latest_by), "latest() requires either a field_name parameter or 'get_latest_by' in the model" return self._clone(_limit=1, _order_by=('-'+latest_by,)).get() - def delete(self, *args, **kwargs): + def delete(self): """ - Deletes the records with the given kwargs. If no kwargs are given, - deletes records in the current QuerySet. + Deletes the records in the current QuerySet. """ - # Remove the DELETE_ALL argument, if it exists. - delete_all = kwargs.pop('DELETE_ALL', False) + del_query = self._clone() - # Check for at least one query argument. - if not kwargs and not delete_all: - raise TypeError, "SAFETY MECHANISM: Specify DELETE_ALL=True if you actually want to delete all data." - - if kwargs: - del_query = self.filter(*args, **kwargs) - else: - del_query = self._clone() # disable non-supported fields del_query._select_related = False - del_query._select = {} del_query._order_by = [] del_query._offset = None del_query._limit = None - # Perform the SQL delete - cursor = connection.cursor() - _, sql, params = del_query._get_sql_clause(False) - cursor.execute("DELETE " + sql, params) - + # Collect all the objects to be deleted, and all the objects that are related to + # the objects that are to be deleted + seen_objs = {} + for object in del_query: + object._collect_sub_objects(seen_objs) + + # Delete the objects + delete_objects(seen_objs) + + # Clear the result cache, in case this QuerySet gets reused. + self._result_cache = None + delete.alters_data = True + ################################################## # PUBLIC METHODS THAT RETURN A QUERYSET SUBCLASS # ################################################## @@ -297,7 +297,7 @@ self._result_cache = list(self.iterator()) return self._result_cache - def _get_sql_clause(self, allow_joins): + def _get_sql_clause(self): opts = self.model._meta # Construct the fundamental parts of the query: SELECT X FROM Y WHERE Z. @@ -325,10 +325,6 @@ # Start composing the body of the SQL statement. sql = [" FROM", backend.quote_name(opts.db_table)] - # Check if extra tables are allowed. If not, throw an error - if (tables or joins) and not allow_joins: - raise TypeError, "Joins are not allowed in this type of query" - # Compose the join dictionary into SQL describing the joins. if joins: sql.append(" ".join(["%s %s AS %s ON %s" % (join_type, table, alias, condition) @@ -407,7 +403,7 @@ field_names = [f.attname for f in self.model._meta.fields] cursor = connection.cursor() - select, sql, params = self._get_sql_clause(True) + select, sql, params = self._get_sql_clause() select = ['%s.%s' % (backend.quote_name(self.model._meta.db_table), backend.quote_name(c)) for c in columns] cursor.execute("SELECT " + (self._distinct and "DISTINCT " or "") + ",".join(select) + sql, params) while 1: @@ -429,7 +425,7 @@ if self._field.null: date_query._where.append('%s.%s IS NOT NULL' % \ (backend.quote_name(self.model._meta.db_table), backend.quote_name(self._field.column))) - select, sql, params = self._get_sql_clause(True) + select, sql, params = self._get_sql_clause() sql = 'SELECT %s %s GROUP BY 1 ORDER BY 1 %s' % \ (backend.get_date_trunc_sql(self._kind, '%s.%s' % (backend.quote_name(self.model._meta.db_table), backend.quote_name(self._field.column))), sql, self._order) @@ -762,3 +758,74 @@ params.extend(field.get_db_prep_lookup(clause, value)) return tables, joins, where, params + +def compare_models(x, y): + "Comparator for Models that puts models in an order where dependencies are easily resolved." + for field in x._meta.fields: + if field.rel and not field.null and field.rel.to == y: + return -1 + for field in y._meta.fields: + if field.rel and not field.null and field.rel.to == x: + return 1 + return 0 + +def delete_objects(seen_objs): + "Iterate through a list of seen classes, and remove any instances that are referred to" + seen_classes = set(seen_objs.keys()) + ordered_classes = list(seen_classes) + ordered_classes.sort(compare_models) + + cursor = connection.cursor() + + for cls in ordered_classes: + seen_objs[cls] = seen_objs[cls].items() + seen_objs[cls].sort() + + # Pre notify all instances to be deleted + for pk_val, instance in seen_objs[cls]: + dispatcher.send(signal=signals.pre_delete, sender=cls, instance=instance) + + pk_list = [pk for pk,instance in seen_objs[cls]] + for related in cls._meta.get_all_related_many_to_many_objects(): + cursor.execute("DELETE FROM %s WHERE %s IN (%s)" % \ + (backend.quote_name(related.field.get_m2m_db_table(related.opts)), + backend.quote_name(cls._meta.object_name.lower() + '_id'), + ','.join('%s' for pk in pk_list)), + pk_list) + for f in cls._meta.many_to_many: + cursor.execute("DELETE FROM %s WHERE %s IN (%s)" % \ + (backend.quote_name(f.get_m2m_db_table(cls._meta)), + backend.quote_name(cls._meta.object_name.lower() + '_id'), + ','.join(['%s' for pk in pk_list])), + pk_list) + for field in cls._meta.fields: + if field.rel and field.null and field.rel.to in seen_classes: + cursor.execute("UPDATE %s SET %s=NULL WHERE %s IN (%s)" % \ + (backend.quote_name(cls._meta.db_table), + backend.quote_name(field.column), + backend.quote_name(cls._meta.pk.column), + ','.join(['%s' for pk in pk_list])), + pk_list) + + # Now delete the actual data + for cls in ordered_classes: + seen_objs[cls].reverse() + pk_list = [pk for pk,instance in seen_objs[cls]] + + cursor.execute("DELETE FROM %s WHERE %s IN (%s)" % \ + (backend.quote_name(cls._meta.db_table), + backend.quote_name(cls._meta.pk.column), + ','.join(['%s' for pk in pk_list])), + pk_list) + + # Last cleanup; set NULLs where there once was a reference to the object, + # NULL the primary key of the found objects, and perform post-notification. + for pk_val, instance in seen_objs[cls]: + for field in cls._meta.fields: + if field.rel and field.null and field.rel.to in seen_classes: + setattr(instance, field.attname, None) + + setattr(instance, cls._meta.pk.attname, None) + dispatcher.send(signal=signals.post_delete, sender=cls, instance=instance) + + connection.commit() Index: tests/modeltests/basic/models.py =================================================================== --- tests/modeltests/basic/models.py (revision 2304) +++ tests/modeltests/basic/models.py (working copy) @@ -9,7 +9,9 @@ class Article(models.Model): headline = models.CharField(maxlength=100, default='Default headline') pub_date = models.DateTimeField() - + + def __repr__(self): + return self.headline API_TESTS = """ # No articles are in the system yet. @@ -37,36 +39,34 @@ >>> a.headline = 'Area woman programs in Python' >>> a.save() -# Article.objects.all() returns all the articles in the database. Note that -# the article is represented by "
", because we haven't given -# the Article model a __repr__() method. +# Article.objects.all() returns all the articles in the database. >>> Article.objects.all() -[
] +[Area woman programs in Python] # Django provides a rich database lookup API. >>> Article.objects.get(id__exact=1) -
+Area woman programs in Python >>> Article.objects.get(headline__startswith='Area woman') -
+Area woman programs in Python >>> Article.objects.get(pub_date__year=2005) -
+Area woman programs in Python >>> Article.objects.get(pub_date__year=2005, pub_date__month=7) -
+Area woman programs in Python >>> Article.objects.get(pub_date__year=2005, pub_date__month=7, pub_date__day=28) -
+Area woman programs in Python # The "__exact" lookup type can be omitted, as a shortcut. >>> Article.objects.get(id=1) -
+Area woman programs in Python >>> Article.objects.get(headline='Area woman programs in Python') -
+Area woman programs in Python >>> Article.objects.filter(pub_date__year=2005) -[
] +[Area woman programs in Python] >>> Article.objects.filter(pub_date__year=2004) [] >>> Article.objects.filter(pub_date__year=2005, pub_date__month=7) -[
] +[Area woman programs in Python] # Django raises an Article.DoesNotExist exception for get() if the parameters # don't match any object. @@ -84,7 +84,7 @@ # shortcut for primary-key exact lookups. # The following is identical to articles.get(id=1). >>> Article.objects.get(pk=1) -
+Area woman programs in Python # Model instances of the same type and same ID are considered equal. >>> a = Article.objects.get(pk=1) @@ -234,12 +234,12 @@ # You can get items using index and slice notation. >>> Article.objects.all()[0] -
+Area woman programs in Python >>> Article.objects.all()[1:3] -[
,
] +[Second article, Third article] >>> s3 = Article.objects.filter(id__exact=3) >>> (s1 | s2 | s3)[::2] -[
,
] +[Area woman programs in Python, Third article] # An Article instance doesn't have access to the "objects" attribute. # That's only available on the class. @@ -254,21 +254,12 @@ AttributeError: Manager isn't accessible via Article instances # Bulk delete test: How many objects before and after the delete? ->>> Article.objects.count() -8L ->>> Article.objects.delete(id__lte=4) ->>> Article.objects.count() -4L +>>> Article.objects.all() +[Area woman programs in Python, Second article, Third article, Fourth article, Article 6, Default headline, Article 7, Updated article 8] +>>> Article.objects.filter(id__lte=4).delete() +>>> Article.objects.all() +[Article 6, Default headline, Article 7, Updated article 8] ->>> Article.objects.delete() -Traceback (most recent call last): - ... -TypeError: SAFETY MECHANISM: Specify DELETE_ALL=True if you actually want to delete all data. - ->>> Article.objects.delete(DELETE_ALL=True) ->>> Article.objects.count() -0L - """ from django.conf import settings Index: tests/modeltests/many_to_many/models.py =================================================================== --- tests/modeltests/many_to_many/models.py (revision 2304) +++ tests/modeltests/many_to_many/models.py (working copy) @@ -162,6 +162,33 @@ >>> p2.article_set.all().order_by('headline') [Oxygen-free diet works wonders] +# Recreate the article and Publication we just deleted. +>>> p1 = Publication(id=None, title='The Python Journal') +>>> p1.save() +>>> a2 = Article(id=None, headline='NASA uses Python') +>>> a2.save() +>>> a2.publications.add(p1, p2, p3) +# Bulk delete some Publications - references to deleted publications should go +>>> Publication.objects.filter(title__startswith='Science').delete() +>>> Publication.objects.all() +[Highlights for Children, The Python Journal] +>>> Article.objects.all() +[Django lets you build Web apps easily, NASA finds intelligent life on Earth, Oxygen-free diet works wonders, NASA uses Python] +>>> a2.publications.all() +[The Python Journal] +# Bulk delete some articles - references to deleted objects should go +>>> q = Article.objects.filter(headline__startswith='Django') +>>> print q +[Django lets you build Web apps easily] +>>> q.delete() + +# After the delete, the QuerySet cache needs to be cleared, and the referenced objects should be gone +>>> print q +[] +>>> p1.article_set.all() +[NASA uses Python] + + """ Index: tests/modeltests/many_to_one/models.py =================================================================== --- tests/modeltests/many_to_one/models.py (revision 2304) +++ tests/modeltests/many_to_one/models.py (working copy) @@ -94,7 +94,7 @@ # The underlying query only makes one join when a related table is referenced twice. >>> query = Article.objects.filter(reporter__first_name__exact='John', reporter__last_name__exact='Smith') ->>> null, sql, null = query._get_sql_clause(True) +>>> null, sql, null = query._get_sql_clause() >>> sql.count('INNER JOIN') 1 @@ -163,21 +163,22 @@ >>> Reporter.objects.filter(article__reporter__first_name__startswith='John').distinct() [John Smith] -# Deletes that require joins are prohibited. ->>> Article.objects.delete(reporter__first_name__startswith='Jo') -Traceback (most recent call last): - ... -TypeError: Joins are not allowed in this type of query - # If you delete a reporter, his articles will be deleted. >>> Article.objects.order_by('headline') [John's second story, Paul's story, This is a test, This is a test, This is a test] >>> Reporter.objects.order_by('first_name') [John Smith, Paul Jones] ->>> r.delete() +>>> r2.delete() >>> Article.objects.order_by('headline') -[Paul's story] +[John's second story, This is a test, This is a test, This is a test] >>> Reporter.objects.order_by('first_name') -[Paul Jones] +[John Smith] +# Deletes using a join in the query +>>> Reporter.objects.filter(article__headline__startswith='This').delete() +>>> Reporter.objects.all() +[] +>>> Article.objects.all() +[] + """