def save(self, must_create=False):
"""
Saves the current session data to the database. If 'must_create' is
True, a database error will be raised if the saving operation doesn't
create a *new* entry (as opposed to possibly updating an existing
entry).
"""
if self.session_key is None:
return self.create()
data = self._get_session(no_load=must_create)
obj = self.create_model_instance(data)
using = router.db_for_write(self.model, instance=obj)
try:
with transaction.atomic(using=using):
obj.save(force_insert=must_create, force_update=not must_create, using=using)
except IntegrityError:
if must_create:
raise CreateError
raise
except DatabaseError:
if not must_create:
raise UpdateError
raise
python类db_for_write()的实例源码
def save(self, must_create=False):
"""
Saves the current session data to the database. If 'must_create' is
True, a database error will be raised if the saving operation doesn't
create a *new* entry (as opposed to possibly updating an existing
entry).
"""
if self.session_key is None:
return self.create()
data = self._get_session(no_load=must_create)
obj = self.create_model_instance(data)
using = router.db_for_write(self.model, instance=obj)
try:
with transaction.atomic(using=using):
obj.save(force_insert=must_create, force_update=not must_create, using=using)
except IntegrityError:
if must_create:
raise CreateError
raise
except DatabaseError:
if not must_create:
raise UpdateError
raise
def init_request(self, object_id, *args, **kwargs):
"The 'delete' admin view for this model."
self.obj = self.get_object(unquote(object_id))
if not self.has_delete_permission(self.obj):
raise PermissionDenied
if self.obj is None:
raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(self.opts.verbose_name), 'key': escape(object_id)})
using = router.db_for_write(self.model)
# Populate deleted_objects, a data structure of all related objects that
# will also be deleted.
(self.deleted_objects, model_count, self.perms_needed, self.protected) = get_deleted_objects(
[self.obj], self.opts, self.request.user, self.admin_site, using)
def init_request(self, object_id, *args, **kwargs):
"The 'delete' admin view for this model."
self.obj = self.get_object(unquote(object_id))
if not self.has_delete_permission(self.obj):
raise PermissionDenied
if self.obj is None:
raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(self.opts.verbose_name), 'key': escape(object_id)})
using = router.db_for_write(self.model)
# Populate deleted_objects, a data structure of all related objects that
# will also be deleted.
(self.deleted_objects, model_count, self.perms_needed, self.protected) = get_deleted_objects(
[self.obj], self.opts, self.request.user, self.admin_site, using)
def init_request(self, object_id, *args, **kwargs):
"The 'delete' admin view for this model."
self.obj = self.get_object(unquote(object_id))
if not self.has_delete_permission(self.obj):
raise PermissionDenied
if self.obj is None:
raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(self.opts.verbose_name), 'key': escape(object_id)})
using = router.db_for_write(self.model)
# Populate deleted_objects, a data structure of all related objects that
# will also be deleted.
(self.deleted_objects, self.perms_needed, self.protected) = get_deleted_objects(
[self.obj], self.opts, self.request.user, self.admin_site, using)
def init_request(self, object_id, *args, **kwargs):
"The 'delete' admin view for this model."
self.obj = self.get_object(unquote(object_id))
if not self.has_delete_permission(self.obj):
raise PermissionDenied
if self.obj is None:
raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_text(self.opts.verbose_name), 'key': escape(object_id)})
using = router.db_for_write(self.model)
# Populate deleted_objects, a data structure of all related objects that
# will also be deleted.
(self.deleted_objects, model_count, self.perms_needed, self.protected) = get_deleted_objects(
[self.obj], self.opts, self.request.user, self.admin_site, using)
def merge_objects(models, group, new_group, limit=1000,
logger=None):
has_more = False
for model in models:
if logger is not None:
logger.info('Merging %r objects where %r into %r', model, group,
new_group)
for obj in model.objects.filter(group=group)[:limit]:
try:
with transaction.atomic(using=router.db_for_write(model)):
model.objects.filter(
id=obj.id
).update(group=new_group)
except IntegrityError:
delete = True
else:
delete = False
if delete:
obj.delete()
has_more = True
if has_more:
return True
return has_more
def save(self, must_create=False):
"""
Saves the current session data to the database. If 'must_create' is
True, a database error will be raised if the saving operation doesn't
create a *new* entry (as opposed to possibly updating an existing
entry).
"""
if self.session_key is None:
return self.create()
data = self._get_session(no_load=must_create)
obj = self.create_model_instance(data)
using = router.db_for_write(self.model, instance=obj)
try:
with transaction.atomic(using=using):
obj.save(force_insert=must_create, using=using)
except IntegrityError:
if must_create:
raise CreateError
raise
def full_restore(self, using=None):
using = using or router.db_for_write(self.__class__, instance=self)
restore_counter = Counter()
if self.deleted:
time = self.deleted_at
else:
return restore_counter
self.collector = models.deletion.Collector(using=using)
self.collector.collect([self])
for model, instances in self.collector.data.items():
instances_to_delete = sorted(instances, key=attrgetter("pk"))
self.sort()
for qs in self.collector.fast_deletes:
# TODO make sure the queryset delete has been made a soft delete
for qs_instance in qs:
restore_counter.update([qs_instance._meta.model_name])
qs_instance.restore(time=time)
for model, instances in self.collector.data.items():
for instance in instances:
restore_counter.update([instance._meta.model_name])
instance.restore(time=time)
return sum(restore_counter.values()), dict(restore_counter)
"""
Restores itself, as well as objects that might have been deleted along with it if cascade is the deletion strategy
"""
self.collector = models.deletion.Collector(using=using)
self.collector.collect([self], keep_parents=keep_parents)
def full_restore(self, using=None):
using = using or router.db_for_write(self.__class__, instance=self)
restore_counter = Counter()
if self.deleted:
time = self.deleted_at
else:
return restore_counter
self.collector = models.deletion.Collector(using=using)
self.collector.collect([self])
for model, instances in self.collector.data.items():
instances_to_delete = sorted(instances, key=attrgetter("pk"))
self.sort()
for qs in self.collector.fast_deletes:
# TODO make sure the queryset delete has been made a soft delete
for qs_instance in qs:
restore_counter.update([qs_instance._meta.model_name])
qs_instance.restore(time=time)
for model, instances in self.collector.data.items():
for instance in instances:
restore_counter.update([instance._meta.model_name])
instance.restore(time=time)
return sum(restore_counter.values()), dict(restore_counter)
"""
Restores itself, as well as objects that might have been deleted along with it if cascade is the deletion strategy
"""
self.collector = models.deletion.Collector(using=using)
self.collector.collect([self], keep_parents=keep_parents)
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def delete(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table, [key])
def clear(self):
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute('DELETE FROM %s' % table)
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def delete(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table, [key])
def clear(self):
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute('DELETE FROM %s' % table)
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def delete(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s WHERE cache_key = %%s" % table, [key])
def clear(self):
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute('DELETE FROM %s' % table)
def add_view(self, request, form_url='', extra_context=None):
with transaction.atomic(using=router.db_for_write(self.model)):
return self._add_view(request, form_url, extra_context)
