632 lines
25 KiB
Python
632 lines
25 KiB
Python
"""
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MySQL database backend for Django.
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Requires mysqlclient: https://pypi.python.org/pypi/mysqlclient/
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MySQLdb is supported for Python 2 only: http://sourceforge.net/projects/mysql-python
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"""
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from __future__ import unicode_literals
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import datetime
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import re
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import sys
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import uuid
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import warnings
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try:
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import MySQLdb as Database
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except ImportError as e:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
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# We want version (1, 2, 1, 'final', 2) or later. We can't just use
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# lexicographic ordering in this check because then (1, 2, 1, 'gamma')
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# inadvertently passes the version test.
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version = Database.version_info
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if (version < (1, 2, 1) or (version[:3] == (1, 2, 1) and
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(len(version) < 5 or version[3] != 'final' or version[4] < 2))):
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("MySQLdb-1.2.1p2 or newer is required; you have %s" % Database.__version__)
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from MySQLdb.converters import conversions, Thing2Literal
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from MySQLdb.constants import FIELD_TYPE, CLIENT
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try:
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import pytz
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except ImportError:
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pytz = None
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from django.conf import settings
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from django.db import utils
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from django.db.backends import (utils as backend_utils, BaseDatabaseFeatures,
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BaseDatabaseOperations, BaseDatabaseWrapper)
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from django.db.backends.mysql.client import DatabaseClient
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from django.db.backends.mysql.creation import DatabaseCreation
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from django.db.backends.mysql.introspection import DatabaseIntrospection
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from django.db.backends.mysql.validation import DatabaseValidation
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from django.utils.encoding import force_str, force_text
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from django.db.backends.mysql.schema import DatabaseSchemaEditor
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from django.utils.functional import cached_property
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from django.utils.safestring import SafeBytes, SafeText
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from django.utils import six
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from django.utils import timezone
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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# It's impossible to import datetime_or_None directly from MySQLdb.times
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parse_datetime = conversions[FIELD_TYPE.DATETIME]
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def parse_datetime_with_timezone_support(value):
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dt = parse_datetime(value)
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# Confirm that dt is naive before overwriting its tzinfo.
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if dt is not None and settings.USE_TZ and timezone.is_naive(dt):
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dt = dt.replace(tzinfo=timezone.utc)
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return dt
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def adapt_datetime_with_timezone_support(value, conv):
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# Equivalent to DateTimeField.get_db_prep_value. Used only by raw SQL.
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if settings.USE_TZ:
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if timezone.is_naive(value):
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warnings.warn("MySQL received a naive datetime (%s)"
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" while time zone support is active." % value,
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RuntimeWarning)
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default_timezone = timezone.get_default_timezone()
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value = timezone.make_aware(value, default_timezone)
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value = value.astimezone(timezone.utc).replace(tzinfo=None)
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return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S.%f"), conv)
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# MySQLdb-1.2.1 returns TIME columns as timedelta -- they are more like
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# timedelta in terms of actual behavior as they are signed and include days --
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# and Django expects time, so we still need to override that. We also need to
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# add special handling for SafeText and SafeBytes as MySQLdb's type
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# checking is too tight to catch those (see Django ticket #6052).
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# Finally, MySQLdb always returns naive datetime objects. However, when
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# timezone support is active, Django expects timezone-aware datetime objects.
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django_conversions = conversions.copy()
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django_conversions.update({
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FIELD_TYPE.TIME: backend_utils.typecast_time,
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FIELD_TYPE.DECIMAL: backend_utils.typecast_decimal,
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FIELD_TYPE.NEWDECIMAL: backend_utils.typecast_decimal,
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FIELD_TYPE.DATETIME: parse_datetime_with_timezone_support,
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datetime.datetime: adapt_datetime_with_timezone_support,
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})
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# This should match the numerical portion of the version numbers (we can treat
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# versions like 5.0.24 and 5.0.24a as the same). Based on the list of version
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# at http://dev.mysql.com/doc/refman/4.1/en/news.html and
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# http://dev.mysql.com/doc/refman/5.0/en/news.html .
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server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')
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# MySQLdb-1.2.1 and newer automatically makes use of SHOW WARNINGS on
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# MySQL-4.1 and newer, so the MysqlDebugWrapper is unnecessary. Since the
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# point is to raise Warnings as exceptions, this can be done with the Python
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# warning module, and this is setup when the connection is created, and the
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# standard backend_utils.CursorDebugWrapper can be used. Also, using sql_mode
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# TRADITIONAL will automatically cause most warnings to be treated as errors.
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class CursorWrapper(object):
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"""
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A thin wrapper around MySQLdb's normal cursor class so that we can catch
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particular exception instances and reraise them with the right types.
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Implemented as a wrapper, rather than a subclass, so that we aren't stuck
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to the particular underlying representation returned by Connection.cursor().
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"""
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codes_for_integrityerror = (1048,)
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def __init__(self, cursor):
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self.cursor = cursor
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def execute(self, query, args=None):
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try:
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# args is None means no string interpolation
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return self.cursor.execute(query, args)
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except Database.OperationalError as e:
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# Map some error codes to IntegrityError, since they seem to be
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# misclassified and Django would prefer the more logical place.
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if e.args[0] in self.codes_for_integrityerror:
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six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
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raise
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def executemany(self, query, args):
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try:
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return self.cursor.executemany(query, args)
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except Database.OperationalError as e:
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# Map some error codes to IntegrityError, since they seem to be
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# misclassified and Django would prefer the more logical place.
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if e.args[0] in self.codes_for_integrityerror:
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six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
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raise
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def __getattr__(self, attr):
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if attr in self.__dict__:
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return self.__dict__[attr]
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else:
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return getattr(self.cursor, attr)
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def __iter__(self):
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return iter(self.cursor)
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def __enter__(self):
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return self
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def __exit__(self, type, value, traceback):
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# Ticket #17671 - Close instead of passing thru to avoid backend
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# specific behavior.
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self.close()
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class DatabaseFeatures(BaseDatabaseFeatures):
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empty_fetchmany_value = ()
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update_can_self_select = False
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allows_group_by_pk = True
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related_fields_match_type = True
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allow_sliced_subqueries = False
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has_bulk_insert = True
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has_select_for_update = True
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has_select_for_update_nowait = False
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supports_forward_references = False
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supports_regex_backreferencing = False
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supports_date_lookup_using_string = False
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can_introspect_autofield = True
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can_introspect_binary_field = False
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can_introspect_small_integer_field = True
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supports_timezones = False
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requires_explicit_null_ordering_when_grouping = True
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allows_auto_pk_0 = False
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uses_savepoints = True
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can_release_savepoints = True
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atomic_transactions = False
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supports_column_check_constraints = False
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@cached_property
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def _mysql_storage_engine(self):
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"Internal method used in Django tests. Don't rely on this from your code"
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with self.connection.cursor() as cursor:
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cursor.execute("SELECT ENGINE FROM INFORMATION_SCHEMA.ENGINES WHERE SUPPORT = 'DEFAULT'")
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result = cursor.fetchone()
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return result[0]
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@cached_property
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def can_introspect_foreign_keys(self):
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"Confirm support for introspected foreign keys"
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return self._mysql_storage_engine != 'MyISAM'
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@cached_property
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def supports_microsecond_precision(self):
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# See https://github.com/farcepest/MySQLdb1/issues/24 for the reason
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# about requiring MySQLdb 1.2.5
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return self.connection.mysql_version >= (5, 6, 4) and Database.version_info >= (1, 2, 5)
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@cached_property
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def has_zoneinfo_database(self):
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# MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects
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# abbreviations (eg. EAT). When pytz isn't installed and the current
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# time zone is LocalTimezone (the only sensible value in this
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# context), the current time zone name will be an abbreviation. As a
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# consequence, MySQL cannot perform time zone conversions reliably.
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if pytz is None:
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return False
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# Test if the time zone definitions are installed.
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with self.connection.cursor() as cursor:
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cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
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return cursor.fetchone() is not None
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def introspected_boolean_field_type(self, *args, **kwargs):
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return 'IntegerField'
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class DatabaseOperations(BaseDatabaseOperations):
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compiler_module = "django.db.backends.mysql.compiler"
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# MySQL stores positive fields as UNSIGNED ints.
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integer_field_ranges = dict(BaseDatabaseOperations.integer_field_ranges,
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PositiveSmallIntegerField=(0, 4294967295),
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PositiveIntegerField=(0, 18446744073709551615),
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)
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def date_extract_sql(self, lookup_type, field_name):
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# http://dev.mysql.com/doc/mysql/en/date-and-time-functions.html
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if lookup_type == 'week_day':
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# DAYOFWEEK() returns an integer, 1-7, Sunday=1.
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# Note: WEEKDAY() returns 0-6, Monday=0.
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return "DAYOFWEEK(%s)" % field_name
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else:
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return "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
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def date_trunc_sql(self, lookup_type, field_name):
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fields = ['year', 'month', 'day', 'hour', 'minute', 'second']
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format = ('%%Y-', '%%m', '-%%d', ' %%H:', '%%i', ':%%s') # Use double percents to escape.
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format_def = ('0000-', '01', '-01', ' 00:', '00', ':00')
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try:
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i = fields.index(lookup_type) + 1
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except ValueError:
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sql = field_name
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else:
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format_str = ''.join([f for f in format[:i]] + [f for f in format_def[i:]])
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sql = "CAST(DATE_FORMAT(%s, '%s') AS DATETIME)" % (field_name, format_str)
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return sql
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def datetime_extract_sql(self, lookup_type, field_name, tzname):
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if settings.USE_TZ:
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field_name = "CONVERT_TZ(%s, 'UTC', %%s)" % field_name
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params = [tzname]
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else:
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params = []
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# http://dev.mysql.com/doc/mysql/en/date-and-time-functions.html
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if lookup_type == 'week_day':
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# DAYOFWEEK() returns an integer, 1-7, Sunday=1.
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# Note: WEEKDAY() returns 0-6, Monday=0.
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sql = "DAYOFWEEK(%s)" % field_name
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else:
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sql = "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
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return sql, params
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def datetime_trunc_sql(self, lookup_type, field_name, tzname):
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if settings.USE_TZ:
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field_name = "CONVERT_TZ(%s, 'UTC', %%s)" % field_name
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params = [tzname]
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else:
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params = []
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fields = ['year', 'month', 'day', 'hour', 'minute', 'second']
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format = ('%%Y-', '%%m', '-%%d', ' %%H:', '%%i', ':%%s') # Use double percents to escape.
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format_def = ('0000-', '01', '-01', ' 00:', '00', ':00')
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try:
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i = fields.index(lookup_type) + 1
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except ValueError:
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sql = field_name
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else:
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format_str = ''.join([f for f in format[:i]] + [f for f in format_def[i:]])
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sql = "CAST(DATE_FORMAT(%s, '%s') AS DATETIME)" % (field_name, format_str)
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return sql, params
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def date_interval_sql(self, timedelta):
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return "INTERVAL '%d 0:0:%d:%d' DAY_MICROSECOND" % (
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timedelta.days, timedelta.seconds, timedelta.microseconds), []
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def format_for_duration_arithmetic(self, sql):
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return 'INTERVAL %s MICROSECOND' % sql
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def drop_foreignkey_sql(self):
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return "DROP FOREIGN KEY"
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def force_no_ordering(self):
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"""
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"ORDER BY NULL" prevents MySQL from implicitly ordering by grouped
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columns. If no ordering would otherwise be applied, we don't want any
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implicit sorting going on.
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"""
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return [(None, ("NULL", [], False))]
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def fulltext_search_sql(self, field_name):
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return 'MATCH (%s) AGAINST (%%s IN BOOLEAN MODE)' % field_name
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def last_executed_query(self, cursor, sql, params):
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# With MySQLdb, cursor objects have an (undocumented) "_last_executed"
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# attribute where the exact query sent to the database is saved.
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# See MySQLdb/cursors.py in the source distribution.
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return force_text(getattr(cursor, '_last_executed', None), errors='replace')
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def no_limit_value(self):
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# 2**64 - 1, as recommended by the MySQL documentation
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return 18446744073709551615
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def quote_name(self, name):
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if name.startswith("`") and name.endswith("`"):
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return name # Quoting once is enough.
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return "`%s`" % name
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def random_function_sql(self):
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return 'RAND()'
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def sql_flush(self, style, tables, sequences, allow_cascade=False):
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# NB: The generated SQL below is specific to MySQL
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# 'TRUNCATE x;', 'TRUNCATE y;', 'TRUNCATE z;'... style SQL statements
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# to clear all tables of all data
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if tables:
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sql = ['SET FOREIGN_KEY_CHECKS = 0;']
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for table in tables:
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sql.append('%s %s;' % (
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style.SQL_KEYWORD('TRUNCATE'),
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style.SQL_FIELD(self.quote_name(table)),
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))
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sql.append('SET FOREIGN_KEY_CHECKS = 1;')
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sql.extend(self.sequence_reset_by_name_sql(style, sequences))
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return sql
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else:
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return []
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def validate_autopk_value(self, value):
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# MySQLism: zero in AUTO_INCREMENT field does not work. Refs #17653.
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if value == 0:
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raise ValueError('The database backend does not accept 0 as a '
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'value for AutoField.')
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return value
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def value_to_db_datetime(self, value):
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if value is None:
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return None
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# MySQL doesn't support tz-aware datetimes
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if timezone.is_aware(value):
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if settings.USE_TZ:
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value = value.astimezone(timezone.utc).replace(tzinfo=None)
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else:
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raise ValueError("MySQL backend does not support timezone-aware datetimes when USE_TZ is False.")
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return six.text_type(value)
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def value_to_db_time(self, value):
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if value is None:
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return None
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# MySQL doesn't support tz-aware times
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if timezone.is_aware(value):
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raise ValueError("MySQL backend does not support timezone-aware times.")
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return six.text_type(value)
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def max_name_length(self):
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return 64
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def bulk_insert_sql(self, fields, num_values):
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items_sql = "(%s)" % ", ".join(["%s"] * len(fields))
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return "VALUES " + ", ".join([items_sql] * num_values)
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def combine_expression(self, connector, sub_expressions):
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"""
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MySQL requires special cases for ^ operators in query expressions
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"""
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if connector == '^':
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return 'POW(%s)' % ','.join(sub_expressions)
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return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
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def get_db_converters(self, expression):
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converters = super(DatabaseOperations, self).get_db_converters(expression)
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internal_type = expression.output_field.get_internal_type()
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if internal_type in ['BooleanField', 'NullBooleanField']:
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converters.append(self.convert_booleanfield_value)
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if internal_type == 'UUIDField':
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converters.append(self.convert_uuidfield_value)
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if internal_type == 'TextField':
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converters.append(self.convert_textfield_value)
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return converters
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def convert_booleanfield_value(self, value, expression, context):
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if value in (0, 1):
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value = bool(value)
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return value
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def convert_uuidfield_value(self, value, expression, context):
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if value is not None:
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value = uuid.UUID(value)
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return value
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def convert_textfield_value(self, value, expression, context):
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if value is not None:
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value = force_text(value)
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return value
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'mysql'
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# This dictionary maps Field objects to their associated MySQL column
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# types, as strings. Column-type strings can contain format strings; they'll
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# be interpolated against the values of Field.__dict__ before being output.
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# If a column type is set to None, it won't be included in the output.
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_data_types = {
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'AutoField': 'integer AUTO_INCREMENT',
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'BinaryField': 'longblob',
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'BooleanField': 'bool',
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'CharField': 'varchar(%(max_length)s)',
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'CommaSeparatedIntegerField': 'varchar(%(max_length)s)',
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'DateField': 'date',
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'DateTimeField': 'datetime',
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'DecimalField': 'numeric(%(max_digits)s, %(decimal_places)s)',
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'DurationField': 'bigint',
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'FileField': 'varchar(%(max_length)s)',
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'FilePathField': 'varchar(%(max_length)s)',
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'FloatField': 'double precision',
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'IntegerField': 'integer',
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'BigIntegerField': 'bigint',
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'IPAddressField': 'char(15)',
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'GenericIPAddressField': 'char(39)',
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'NullBooleanField': 'bool',
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'OneToOneField': 'integer',
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'PositiveIntegerField': 'integer UNSIGNED',
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'PositiveSmallIntegerField': 'smallint UNSIGNED',
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'SlugField': 'varchar(%(max_length)s)',
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'SmallIntegerField': 'smallint',
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'TextField': 'longtext',
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'TimeField': 'time',
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'UUIDField': 'char(32)',
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}
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@cached_property
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def data_types(self):
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if self.features.supports_microsecond_precision:
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return dict(self._data_types, DateTimeField='datetime(6)', TimeField='time(6)')
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else:
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return self._data_types
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operators = {
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'exact': '= %s',
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'iexact': 'LIKE %s',
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'contains': 'LIKE BINARY %s',
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'icontains': 'LIKE %s',
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'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',
|
|
}
|
|
|
|
# The patterns below are used to generate SQL pattern lookup clauses when
|
|
# the right-hand side of the lookup isn't a raw string (it might be an expression
|
|
# or the result of a bilateral transformation).
|
|
# In those cases, special characters for LIKE operators (e.g. \, *, _) should be
|
|
# escaped on database side.
|
|
#
|
|
# Note: we use str.format() here for readability as '%' is used as a wildcard for
|
|
# the LIKE operator.
|
|
pattern_esc = r"REPLACE(REPLACE(REPLACE({}, '\\', '\\\\'), '%%', '\%%'), '_', '\_')"
|
|
pattern_ops = {
|
|
'contains': "LIKE BINARY CONCAT('%%', {}, '%%')",
|
|
'icontains': "LIKE CONCAT('%%', {}, '%%')",
|
|
'startswith': "LIKE BINARY CONCAT({}, '%%')",
|
|
'istartswith': "LIKE CONCAT({}, '%%')",
|
|
'endswith': "LIKE BINARY CONCAT('%%', {})",
|
|
'iendswith': "LIKE CONCAT('%%', {})",
|
|
}
|
|
|
|
Database = Database
|
|
SchemaEditorClass = DatabaseSchemaEditor
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(DatabaseWrapper, self).__init__(*args, **kwargs)
|
|
|
|
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 get_connection_params(self):
|
|
kwargs = {
|
|
'conv': django_conversions,
|
|
'charset': 'utf8',
|
|
}
|
|
if six.PY2:
|
|
kwargs['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'] = force_str(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'])
|
|
return kwargs
|
|
|
|
def get_new_connection(self, conn_params):
|
|
conn = Database.connect(**conn_params)
|
|
conn.encoders[SafeText] = conn.encoders[six.text_type]
|
|
conn.encoders[SafeBytes] = conn.encoders[bytes]
|
|
return conn
|
|
|
|
def init_connection_state(self):
|
|
with self.cursor() as cursor:
|
|
# 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')
|
|
|
|
def create_cursor(self):
|
|
cursor = self.connection.cursor()
|
|
return CursorWrapper(cursor)
|
|
|
|
def _rollback(self):
|
|
try:
|
|
BaseDatabaseWrapper._rollback(self)
|
|
except Database.NotSupportedError:
|
|
pass
|
|
|
|
def _set_autocommit(self, autocommit):
|
|
with self.wrap_database_errors:
|
|
self.connection.autocommit(autocommit)
|
|
|
|
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.
|
|
"""
|
|
# Override needs_rollback in case constraint_checks_disabled is
|
|
# nested inside transaction.atomic.
|
|
self.needs_rollback, needs_rollback = False, self.needs_rollback
|
|
try:
|
|
self.cursor().execute('SET foreign_key_checks=1')
|
|
finally:
|
|
self.needs_rollback = needs_rollback
|
|
|
|
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))
|
|
|
|
def is_usable(self):
|
|
try:
|
|
self.connection.ping()
|
|
except Database.Error:
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
@cached_property
|
|
def mysql_version(self):
|
|
with self.temporary_connection():
|
|
server_info = self.connection.get_server_info()
|
|
match = server_version_re.match(server_info)
|
|
if not match:
|
|
raise Exception('Unable to determine MySQL version from version string %r' % server_info)
|
|
return tuple(int(x) for x in match.groups())
|