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- from django.db.backends.base.features import BaseDatabaseFeatures
- from django.utils.functional import cached_property
-
- from .base import Database
-
- try:
- import pytz
- except ImportError:
- pytz = None
-
-
- class DatabaseFeatures(BaseDatabaseFeatures):
- empty_fetchmany_value = ()
- update_can_self_select = False
- allows_group_by_pk = True
- related_fields_match_type = True
- allow_sliced_subqueries = False
- has_bulk_insert = True
- has_select_for_update = True
- has_select_for_update_nowait = False
- 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_small_integer_field = True
- supports_timezones = False
- requires_explicit_null_ordering_when_grouping = True
- allows_auto_pk_0 = False
- uses_savepoints = True
- can_release_savepoints = True
- atomic_transactions = False
- supports_column_check_constraints = False
- can_clone_databases = True
-
- @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 supports_microsecond_precision(self):
- # See https://github.com/farcepest/MySQLdb1/issues/24 for the reason
- # about requiring MySQLdb 1.2.5
- return self.connection.mysql_version >= (5, 6, 4) and Database.version_info >= (1, 2, 5)
-
- @cached_property
- def has_zoneinfo_database(self):
- # MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects
- # abbreviations (eg. EAT). When pytz isn't installed and the current
- # time zone is LocalTimezone (the only sensible value in this
- # context), the current time zone name will be an abbreviation. As a
- # consequence, MySQL cannot perform time zone conversions reliably.
- if pytz is None:
- return False
-
- # Test if the time zone definitions are installed.
- with self.connection.cursor() as cursor:
- cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
- return cursor.fetchone() is not None
-
- def introspected_boolean_field_type(self, *args, **kwargs):
- return 'IntegerField'
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