# MySQL Connector/Python - MySQL driver written in Python.
# New file added for Django 1.8
import django
if django.VERSION >= (1, 8):
from django.db.backends.base.features import BaseDatabaseFeatures
else:
from django.db.backends import BaseDatabaseFeatures
from django.utils.functional import cached_property
from django.utils import six
try:
import pytz
HAVE_PYTZ = True
except ImportError:
HAVE_PYTZ = False
class DatabaseFeatures(BaseDatabaseFeatures):
"""Features specific to MySQL
Microsecond precision is supported since MySQL 5.6.3 and turned on
by default if this MySQL version is used.
"""
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
allows_primary_key_0 = False
uses_savepoints = True
atomic_transactions = False
supports_column_check_constraints = False
if django.VERSION < (1, 8):
supports_long_model_names = False
supports_binary_field = six.PY2
can_introspect_boolean_field = False
def __init__(self, connection):
super(DatabaseFeatures, self).__init__(connection)
@cached_property
def supports_microsecond_precision(self):
if self.connection.mysql_version >= (5, 6, 3):
return True
return False
@cached_property
def mysql_storage_engine(self):
"""Get default storage engine of MySQL
This method creates a table without ENGINE table option and inspects
which engine was used.
Used by Django tests.
"""
tblname = 'INTROSPECT_TEST'
droptable = 'DROP TABLE IF EXISTS {table}'.format(table=tblname)
with self.connection.cursor() as cursor:
cursor.execute(droptable)
cursor.execute('CREATE TABLE {table} (X INT)'.format(table=tblname))
if self.connection.mysql_version >= (5, 0, 0):
cursor.execute(
"SELECT ENGINE FROM INFORMATION_SCHEMA.TABLES "
"WHERE TABLE_SCHEMA = %s AND TABLE_NAME = %s",
(self.connection.settings_dict['NAME'], tblname))
engine = cursor.fetchone()[0]
else:
# Very old MySQL servers..
cursor.execute("SHOW TABLE STATUS WHERE Name='{table}'".format(
table=tblname))
engine = cursor.fetchone()[1]
cursor.execute(droptable)
self._cached_storage_engine = engine
return engine
@cached_property
def _disabled_supports_transactions(self):
return self.mysql_storage_engine == 'InnoDB'
@cached_property
def can_introspect_foreign_keys(self):
"""Confirm support for introspected foreign keys
Only the InnoDB storage engine supports Foreigen Key (not taking
into account MySQL Cluster here).
"""
return self.mysql_storage_engine == 'InnoDB'
@cached_property
def has_zoneinfo_database(self):
"""Tests if the time zone definitions are installed
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.
"""
# Django 1.6
if not HAVE_PYTZ:
return False
with self.connection.cursor() as cursor:
cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
return cursor.fetchall() != []
def introspected_boolean_field_type(self, *args, **kwargs):
# New in Django 1.8
return 'IntegerField'
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