import operator from django.db.backends.base.features import BaseDatabaseFeatures from django.utils.functional import cached_property class DatabaseFeatures(BaseDatabaseFeatures): empty_fetchmany_value = () update_can_self_select = False allows_group_by_pk = True related_fields_match_type = True # MySQL doesn't support sliced subqueries with IN/ALL/ANY/SOME. allow_sliced_subqueries_with_in = False has_select_for_update = True supports_forward_references = False supports_regex_backreferencing = False supports_date_lookup_using_string = False can_introspect_autofield = True can_introspect_binary_field = False can_introspect_duration_field = False can_introspect_small_integer_field = True can_introspect_positive_integer_field = True introspected_boolean_field_type = 'IntegerField' supports_index_column_ordering = False supports_timezones = False requires_explicit_null_ordering_when_grouping = True allows_auto_pk_0 = False can_release_savepoints = True atomic_transactions = False can_clone_databases = True supports_temporal_subtraction = True supports_select_intersection = False supports_select_difference = False supports_slicing_ordering_in_compound = True supports_index_on_text_field = False has_case_insensitive_like = False create_test_procedure_without_params_sql = """ CREATE PROCEDURE test_procedure () BEGIN DECLARE V_I INTEGER; SET V_I = 1; END; """ create_test_procedure_with_int_param_sql = """ CREATE PROCEDURE test_procedure (P_I INTEGER) BEGIN DECLARE V_I INTEGER; SET V_I = P_I; END; """ db_functions_convert_bytes_to_str = True # Alias MySQL's TRADITIONAL to TEXT for consistency with other backends. supported_explain_formats = {'JSON', 'TEXT', 'TRADITIONAL'} # Neither MySQL nor MariaDB support partial indexes. supports_partial_indexes = False @cached_property def _mysql_storage_engine(self): "Internal method used in Django tests. Don't rely on this from your code" with self.connection.cursor() as cursor: cursor.execute("SELECT ENGINE FROM INFORMATION_SCHEMA.ENGINES WHERE SUPPORT = 'DEFAULT'") result = cursor.fetchone() return result[0] @cached_property def can_introspect_foreign_keys(self): "Confirm support for introspected foreign keys" return self._mysql_storage_engine != 'MyISAM' @cached_property def has_zoneinfo_database(self): # Test if the time zone definitions are installed. CONVERT_TZ returns # NULL if 'UTC' timezone isn't loaded into the mysql.time_zone. with self.connection.cursor() as cursor: cursor.execute("SELECT CONVERT_TZ('2001-01-01 01:00:00', 'UTC', 'UTC')") return cursor.fetchone()[0] is not None @cached_property def is_sql_auto_is_null_enabled(self): with self.connection.cursor() as cursor: cursor.execute('SELECT @@SQL_AUTO_IS_NULL') result = cursor.fetchone() return result and result[0] == 1 @cached_property def supports_over_clause(self): if self.connection.mysql_is_mariadb: return self.connection.mysql_version >= (10, 2) return self.connection.mysql_version >= (8, 0, 2) @cached_property def supports_column_check_constraints(self): if self.connection.mysql_is_mariadb: return self.connection.mysql_version >= (10, 2, 1) return self.connection.mysql_version >= (8, 0, 16) supports_table_check_constraints = property(operator.attrgetter('supports_column_check_constraints')) @cached_property def can_introspect_check_constraints(self): if self.connection.mysql_is_mariadb: version = self.connection.mysql_version return (version >= (10, 2, 22) and version < (10, 3)) or version >= (10, 3, 10) return self.connection.mysql_version >= (8, 0, 16) @cached_property def has_select_for_update_skip_locked(self): return not self.connection.mysql_is_mariadb and self.connection.mysql_version >= (8, 0, 1) @cached_property def has_select_for_update_nowait(self): if self.connection.mysql_is_mariadb: return self.connection.mysql_version >= (10, 3, 0) return self.connection.mysql_version >= (8, 0, 1) @cached_property def needs_explain_extended(self): # EXTENDED is deprecated (and not required) in MySQL 5.7. return not self.connection.mysql_is_mariadb and self.connection.mysql_version < (5, 7) @cached_property def supports_transactions(self): """ All storage engines except MyISAM support transactions. """ return self._mysql_storage_engine != 'MyISAM' @cached_property def ignores_table_name_case(self): with self.connection.cursor() as cursor: cursor.execute('SELECT @@LOWER_CASE_TABLE_NAMES') result = cursor.fetchone() return result and result[0] != 0 @cached_property def supports_default_in_lead_lag(self): # To be added in https://jira.mariadb.org/browse/MDEV-12981. return not self.connection.mysql_is_mariadb