def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
python类Collector()的实例源码
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def get_context_data(self, **kwargs):
context = super(DynamicDeleteView, self).get_context_data(**kwargs)
collector = Collector(using='default') # or specific database
collector.collect([self.object])
to_delete = collector.instances_with_model()
context['to_delete_list'] = []
for x, y in to_delete:
context['to_delete_list'].append((x.__name__, y,))
return context
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def delete(self):
"""
Deletes the records in the current QuerySet.
"""
assert self.query.can_filter(), \
"Cannot use 'limit' or 'offset' with delete."
if self._fields is not None:
raise TypeError("Cannot call delete() after .values() or .values_list()")
del_query = self._clone()
# The delete is actually 2 queries - one to find related objects,
# and one to delete. Make sure that the discovery of related
# objects is performed on the same database as the deletion.
del_query._for_write = True
# Disable non-supported fields.
del_query.query.select_for_update = False
del_query.query.select_related = False
del_query.query.clear_ordering(force_empty=True)
collector = Collector(using=del_query.db)
collector.collect(del_query)
deleted, _rows_count = collector.delete()
# Clear the result cache, in case this QuerySet gets reused.
self._result_cache = None
return deleted, _rows_count
def delete(self, using=None, keep_parents=False):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self], keep_parents=keep_parents)
return collector.delete()
def test_integrity_error_is_retried(self):
# This doesn't simulate the actual way the failure is caused, but it
# does simulate it to cause the same effect.
#
# The `calls` below is used to hold the context inside of the retry
# loop. The first call will fail as `_clear_events` will be called,
# the first retry will not call `_clear_events` which will allow the
# transaction to be committed.
calls = []
def _clear_events(collector):
for idx, objs in enumerate(collector.fast_deletes):
if len(objs) > 0 and isinstance(objs[0], Event):
collector.fast_deletes[idx] = Event.objects.none()
@transactional
def _in_database():
node = factory.make_Node()
for _ in range(10):
factory.make_Event(node=node)
# Use the collector directly instead of calling `delete`.
collector = Collector(using="default")
collector.collect([node])
if calls == 0:
_clear_events(collector)
calls.append(None)
collector.delete()
# Test is that no exception is raised. If this doesn't work then a
# `django.db.utils.IntegrityError` will be raised.
yield deferToDatabase(_in_database)
def delete(self, using=None):
using = using or router.db_for_write(self.__class__, instance=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)
)
collector = Collector(using=using)
collector.collect([self])
collector.delete()
