def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
self.server_version = None
self.features = DatabaseFeatures(self)
self.ops = DatabaseOperations(self)
self.client = DatabaseClient(self)
self.creation = DatabaseCreation(self)
self.introspection = DatabaseIntrospection(self)
self.validation = DatabaseValidation(self)
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = 'mysql'
operators = {
'exact': '= %s',
'iexact': 'LIKE %s',
'contains': 'LIKE BINARY %s',
'icontains': 'LIKE %s',
'regex': 'REGEXP BINARY %s',
'iregex': 'REGEXP %s',
'gt': '> %s',
'gte': '>= %s',
'lt': '< %s',
'lte': '<= %s',
'startswith': 'LIKE BINARY %s',
'endswith': 'LIKE BINARY %s',
'istartswith': 'LIKE %s',
'iendswith': 'LIKE %s',
}
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
self.server_version = None
self.features = DatabaseFeatures(self)
self.ops = DatabaseOperations(self)
self.client = DatabaseClient(self)
self.creation = DatabaseCreation(self)
self.introspection = DatabaseIntrospection(self)
self.validation = DatabaseValidation(self)
def _valid_connection(self):
if self.connection is not None:
try:
self.connection.ping()
return True
except DatabaseError:
self.connection.close()
self.connection = None
return False
def _cursor(self):
new_connection = False
if not self._valid_connection():
new_connection = True
kwargs = {
'conv': django_conversions,
'charset': 'utf8',
'use_unicode': True,
}
settings_dict = self.settings_dict
if settings_dict['USER']:
kwargs['user'] = settings_dict['USER']
if settings_dict['NAME']:
kwargs['db'] = settings_dict['NAME']
if settings_dict['PASSWORD']:
kwargs['passwd'] = settings_dict['PASSWORD']
if settings_dict['HOST'].startswith('/'):
kwargs['unix_socket'] = settings_dict['HOST']
elif settings_dict['HOST']:
kwargs['host'] = settings_dict['HOST']
if settings_dict['PORT']:
kwargs['port'] = int(settings_dict['PORT'])
# We need the number of potentially affected rows after an
# "UPDATE", not the number of changed rows.
kwargs['client_flag'] = CLIENT.FOUND_ROWS
kwargs.update(settings_dict['OPTIONS'])
self.connection = Database.connect(**kwargs)
self.connection.encoders[SafeText] = self.connection.encoders[six.text_type]
self.connection.encoders[SafeBytes] = self.connection.encoders[bytes]
connection_created.send(sender=self.__class__, connection=self)
cursor = self.connection.cursor()
if new_connection:
# SQL_AUTO_IS_NULL in MySQL controls whether an AUTO_INCREMENT column
# on a recently-inserted row will return when the field is tested for
# NULL. Disabling this value brings this aspect of MySQL in line with
# SQL standards.
cursor.execute('SET SQL_AUTO_IS_NULL = 0')
return CursorWrapper(cursor)
def _rollback(self):
try:
BaseDatabaseWrapper._rollback(self)
except Database.NotSupportedError:
pass
@cached_property
def mysql_version(self):
if not self.server_version:
new_connection = False
if not self._valid_connection():
# Ensure we have a connection with the DB by using a temporary
# cursor
new_connection = True
self.cursor().close()
server_info = self.connection.get_server_info()
if new_connection:
# Make sure we close the connection
self.connection.close()
self.connection = None
m = server_version_re.match(server_info)
if not m:
raise Exception('Unable to determine MySQL version from version string %r' % server_info)
self.server_version = tuple([int(x) for x in m.groups()])
return self.server_version
def disable_constraint_checking(self):
"""
Disables foreign key checks, primarily for use in adding rows with forward references. Always returns True,
to indicate constraint checks need to be re-enabled.
"""
self.cursor().execute('SET foreign_key_checks=0')
return True
def enable_constraint_checking(self):
"""
Re-enable foreign key checks after they have been disabled.
"""
self.cursor().execute('SET foreign_key_checks=1')
def check_constraints(self, table_names=None):
"""
Checks each table name in `table_names` for rows with invalid foreign key references. This method is
intended to be used in conjunction with `disable_constraint_checking()` and `enable_constraint_checking()`, to
determine if rows with invalid references were entered while constraint checks were off.
Raises an IntegrityError on the first invalid foreign key reference encountered (if any) and provides
detailed information about the invalid reference in the error message.
Backends can override this method if they can more directly apply constraint checking (e.g. via "SET CONSTRAINTS
ALL IMMEDIATE")
"""
cursor = self.cursor()
if table_names is None:
table_names = self.introspection.table_names(cursor)
for table_name in table_names:
primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
if not primary_key_column_name:
continue
key_columns = self.introspection.get_key_columns(cursor, table_name)
for column_name, referenced_table_name, referenced_column_name in key_columns:
cursor.execute("""
SELECT REFERRING.`%s`, REFERRING.`%s` FROM `%s` as REFERRING
LEFT JOIN `%s` as REFERRED
ON (REFERRING.`%s` = REFERRED.`%s`)
WHERE REFERRING.`%s` IS NOT NULL AND REFERRED.`%s` IS NULL"""
% (primary_key_column_name, column_name, table_name, referenced_table_name,
column_name, referenced_column_name, column_name, referenced_column_name))
for bad_row in cursor.fetchall():
raise utils.IntegrityError("The row in table '%s' with primary key '%s' has an invalid "
"foreign key: %s.%s contains a value '%s' that does not have a corresponding value in %s.%s."
% (table_name, bad_row[0],
table_name, column_name, bad_row[1],
referenced_table_name, referenced_column_name))
