466 lines
20 KiB
Python
466 lines
20 KiB
Python
"""
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MySQL database backend for Django.
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Requires MySQLdb: http://sourceforge.net/projects/mysql-python
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"""
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import datetime
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import re
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import sys
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try:
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import MySQLdb as Database
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except ImportError, 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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from django.db import utils
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from django.db.backends import *
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from django.db.backends.signals import connection_created
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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.safestring import SafeString, SafeUnicode
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from django.utils import timezone
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# Raise exceptions for database warnings if DEBUG is on
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from django.conf import settings
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if settings.DEBUG:
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from warnings import filterwarnings
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filterwarnings("error", category=Database.Warning)
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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(u"SQLite received a naive datetime (%s)"
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u" 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"), 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 SafeUnicode and SafeString 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: util.typecast_time,
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FIELD_TYPE.DECIMAL: util.typecast_decimal,
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FIELD_TYPE.NEWDECIMAL: util.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 util.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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return self.cursor.execute(query, args)
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except Database.IntegrityError, e:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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except Database.OperationalError, 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[0] in self.codes_for_integrityerror:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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except Database.DatabaseError, e:
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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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.IntegrityError, e:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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except Database.OperationalError, 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[0] in self.codes_for_integrityerror:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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except Database.DatabaseError, e:
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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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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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_long_model_names = False
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supports_microsecond_precision = False
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supports_regex_backreferencing = False
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supports_date_lookup_using_string = False
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supports_timezones = False
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requires_explicit_null_ordering_when_grouping = True
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allows_primary_key_0 = False
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def __init__(self, connection):
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super(DatabaseFeatures, self).__init__(connection)
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self._storage_engine = None
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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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if self._storage_engine is None:
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cursor = self.connection.cursor()
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cursor.execute('CREATE TABLE INTROSPECT_TEST (X INT)')
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# This command is MySQL specific; the second column
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# will tell you the default table type of the created
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# table. Since all Django's test tables will have the same
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# table type, that's enough to evaluate the feature.
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cursor.execute("SHOW TABLE STATUS WHERE Name='INTROSPECT_TEST'")
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result = cursor.fetchone()
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cursor.execute('DROP TABLE INTROSPECT_TEST')
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self._storage_engine = result[1]
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return self._storage_engine
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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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class DatabaseOperations(BaseDatabaseOperations):
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compiler_module = "django.db.backends.mysql.compiler"
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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 date_interval_sql(self, sql, connector, timedelta):
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return "(%s %s INTERVAL '%d 0:0:%d:%d' DAY_MICROSECOND)" % (sql, connector,
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timedelta.days, timedelta.seconds, timedelta.microseconds)
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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 ["NULL"]
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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 cursor._last_executed
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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 18446744073709551615L
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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):
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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;' % (style.SQL_KEYWORD('TRUNCATE'), style.SQL_FIELD(self.quote_name(table))))
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sql.append('SET FOREIGN_KEY_CHECKS = 1;')
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# 'ALTER TABLE table AUTO_INCREMENT = 1;'... style SQL statements
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# to reset sequence indices
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sql.extend(["%s %s %s %s %s;" % \
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(style.SQL_KEYWORD('ALTER'),
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style.SQL_KEYWORD('TABLE'),
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style.SQL_TABLE(self.quote_name(sequence['table'])),
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style.SQL_KEYWORD('AUTO_INCREMENT'),
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style.SQL_FIELD('= 1'),
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) for sequence in sequences])
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return sql
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else:
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return []
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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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# MySQL doesn't support microseconds
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return unicode(value.replace(microsecond=0))
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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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# MySQL doesn't support microseconds
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return unicode(value.replace(microsecond=0))
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def year_lookup_bounds(self, value):
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# Again, no microseconds
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first = '%s-01-01 00:00:00'
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second = '%s-12-31 23:59:59.99'
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return [first % value, second % 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 savepoint_create_sql(self, sid):
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return "SAVEPOINT %s" % sid
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def savepoint_commit_sql(self, sid):
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return "RELEASE SAVEPOINT %s" % sid
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def savepoint_rollback_sql(self, sid):
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return "ROLLBACK TO SAVEPOINT %s" % sid
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'mysql'
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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',
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'iregex': 'REGEXP %s',
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'gt': '> %s',
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'gte': '>= %s',
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'lt': '< %s',
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'lte': '<= %s',
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'startswith': 'LIKE BINARY %s',
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'endswith': 'LIKE BINARY %s',
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'istartswith': 'LIKE %s',
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'iendswith': 'LIKE %s',
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}
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def __init__(self, *args, **kwargs):
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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self.server_version = None
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self.features = DatabaseFeatures(self)
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self.ops = DatabaseOperations(self)
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self.client = DatabaseClient(self)
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self.creation = DatabaseCreation(self)
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self.introspection = DatabaseIntrospection(self)
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self.validation = DatabaseValidation(self)
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def _valid_connection(self):
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if self.connection is not None:
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try:
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self.connection.ping()
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return True
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except DatabaseError:
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self.connection.close()
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self.connection = None
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return False
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def _cursor(self):
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new_connection = False
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if not self._valid_connection():
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new_connection = True
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kwargs = {
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'conv': django_conversions,
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'charset': 'utf8',
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'use_unicode': True,
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}
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settings_dict = self.settings_dict
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if settings_dict['USER']:
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kwargs['user'] = settings_dict['USER']
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if settings_dict['NAME']:
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kwargs['db'] = settings_dict['NAME']
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if settings_dict['PASSWORD']:
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kwargs['passwd'] = settings_dict['PASSWORD']
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if settings_dict['HOST'].startswith('/'):
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kwargs['unix_socket'] = settings_dict['HOST']
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elif settings_dict['HOST']:
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kwargs['host'] = settings_dict['HOST']
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if settings_dict['PORT']:
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kwargs['port'] = int(settings_dict['PORT'])
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# We need the number of potentially affected rows after an
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# "UPDATE", not the number of changed rows.
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kwargs['client_flag'] = CLIENT.FOUND_ROWS
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kwargs.update(settings_dict['OPTIONS'])
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self.connection = Database.connect(**kwargs)
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self.connection.encoders[SafeUnicode] = self.connection.encoders[unicode]
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self.connection.encoders[SafeString] = self.connection.encoders[str]
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self.features.uses_savepoints = \
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self.get_server_version() >= (5, 0, 3)
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connection_created.send(sender=self.__class__, connection=self)
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cursor = self.connection.cursor()
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if new_connection:
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# SQL_AUTO_IS_NULL in MySQL controls whether an AUTO_INCREMENT column
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# on a recently-inserted row will return when the field is tested for
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# NULL. Disabling this value brings this aspect of MySQL in line with
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# SQL standards.
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cursor.execute('SET SQL_AUTO_IS_NULL = 0')
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return CursorWrapper(cursor)
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def _rollback(self):
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try:
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BaseDatabaseWrapper._rollback(self)
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except Database.NotSupportedError:
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pass
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def get_server_version(self):
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if not self.server_version:
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if not self._valid_connection():
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self.cursor()
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m = server_version_re.match(self.connection.get_server_info())
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if not m:
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raise Exception('Unable to determine MySQL version from version string %r' % self.connection.get_server_info())
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self.server_version = tuple([int(x) for x in m.groups()])
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return self.server_version
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def disable_constraint_checking(self):
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"""
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Disables foreign key checks, primarily for use in adding rows with forward references. Always returns True,
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to indicate constraint checks need to be re-enabled.
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"""
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self.cursor().execute('SET foreign_key_checks=0')
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return True
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def enable_constraint_checking(self):
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"""
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Re-enable foreign key checks after they have been disabled.
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"""
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self.cursor().execute('SET foreign_key_checks=1')
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def check_constraints(self, table_names=None):
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"""
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Checks each table name in `table_names` for rows with invalid foreign key references. This method is
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intended to be used in conjunction with `disable_constraint_checking()` and `enable_constraint_checking()`, to
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determine if rows with invalid references were entered while constraint checks were off.
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Raises an IntegrityError on the first invalid foreign key reference encountered (if any) and provides
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detailed information about the invalid reference in the error message.
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Backends can override this method if they can more directly apply constraint checking (e.g. via "SET CONSTRAINTS
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ALL IMMEDIATE")
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"""
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cursor = self.cursor()
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if table_names is None:
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table_names = self.introspection.get_table_list(cursor)
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for table_name in table_names:
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primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
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if not primary_key_column_name:
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continue
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key_columns = self.introspection.get_key_columns(cursor, table_name)
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for column_name, referenced_table_name, referenced_column_name in key_columns:
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cursor.execute("""
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SELECT REFERRING.`%s`, REFERRING.`%s` FROM `%s` as REFERRING
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LEFT JOIN `%s` as REFERRED
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ON (REFERRING.`%s` = REFERRED.`%s`)
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|
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))
|