django1/django/db/backends/mysql/base.py

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"""
MySQL database backend for Django.
Requires MySQLdb: http://sourceforge.net/projects/mysql-python
"""
import re
import sys
try:
import MySQLdb as Database
except ImportError, e:
from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
# We want version (1, 2, 1, 'final', 2) or later. We can't just use
# lexicographic ordering in this check because then (1, 2, 1, 'gamma')
# inadvertently passes the version test.
version = Database.version_info
if (version < (1,2,1) or (version[:3] == (1, 2, 1) and
(len(version) < 5 or version[3] != 'final' or version[4] < 2))):
from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured("MySQLdb-1.2.1p2 or newer is required; you have %s" % Database.__version__)
from MySQLdb.converters import conversions
from MySQLdb.constants import FIELD_TYPE, FLAG, CLIENT
from django.db import utils
from django.db.backends import *
from django.db.backends.signals import connection_created
from django.db.backends.mysql.client import DatabaseClient
from django.db.backends.mysql.creation import DatabaseCreation
from django.db.backends.mysql.introspection import DatabaseIntrospection
from django.db.backends.mysql.validation import DatabaseValidation
from django.utils.safestring import SafeString, SafeUnicode
# Raise exceptions for database warnings if DEBUG is on
from django.conf import settings
if settings.DEBUG:
from warnings import filterwarnings
filterwarnings("error", category=Database.Warning)
DatabaseError = Database.DatabaseError
IntegrityError = Database.IntegrityError
# MySQLdb-1.2.1 returns TIME columns as timedelta -- they are more like
# timedelta in terms of actual behavior as they are signed and include days --
# and Django expects time, so we still need to override that. We also need to
# add special handling for SafeUnicode and SafeString as MySQLdb's type
# checking is too tight to catch those (see Django ticket #6052).
django_conversions = conversions.copy()
django_conversions.update({
FIELD_TYPE.TIME: util.typecast_time,
FIELD_TYPE.DECIMAL: util.typecast_decimal,
FIELD_TYPE.NEWDECIMAL: util.typecast_decimal,
})
# This should match the numerical portion of the version numbers (we can treat
# versions like 5.0.24 and 5.0.24a as the same). Based on the list of version
# at http://dev.mysql.com/doc/refman/4.1/en/news.html and
# http://dev.mysql.com/doc/refman/5.0/en/news.html .
server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')
# MySQLdb-1.2.1 and newer automatically makes use of SHOW WARNINGS on
# MySQL-4.1 and newer, so the MysqlDebugWrapper is unnecessary. Since the
# point is to raise Warnings as exceptions, this can be done with the Python
# warning module, and this is setup when the connection is created, and the
# standard util.CursorDebugWrapper can be used. Also, using sql_mode
# TRADITIONAL will automatically cause most warnings to be treated as errors.
class CursorWrapper(object):
"""
A thin wrapper around MySQLdb's normal cursor class so that we can catch
particular exception instances and reraise them with the right types.
Implemented as a wrapper, rather than a subclass, so that we aren't stuck
to the particular underlying representation returned by Connection.cursor().
"""
codes_for_integrityerror = (1048,)
def __init__(self, cursor):
self.cursor = cursor
def execute(self, query, args=None):
try:
return self.cursor.execute(query, args)
except Database.IntegrityError, e:
raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
except Database.OperationalError, e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e[0] in self.codes_for_integrityerror:
raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
raise
except Database.DatabaseError, e:
raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
def executemany(self, query, args):
try:
return self.cursor.executemany(query, args)
except Database.IntegrityError, e:
raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
except Database.OperationalError, e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e[0] in self.codes_for_integrityerror:
raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
raise
except Database.DatabaseError, e:
raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
def __getattr__(self, attr):
if attr in self.__dict__:
return self.__dict__[attr]
else:
return getattr(self.cursor, attr)
def __iter__(self):
return iter(self.cursor)
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
supports_forward_references = False
supports_long_model_names = False
supports_microsecond_precision = False
supports_regex_backreferencing = False
supports_date_lookup_using_string = False
supports_timezones = False
requires_explicit_null_ordering_when_grouping = True
allows_primary_key_0 = False
def _can_introspect_foreign_keys(self):
"Confirm support for introspected foreign keys"
cursor = self.connection.cursor()
cursor.execute('CREATE TABLE INTROSPECT_TEST (X INT)')
# This command is MySQL specific; the second column
# will tell you the default table type of the created
# table. Since all Django's test tables will have the same
# table type, that's enough to evaluate the feature.
cursor.execute('SHOW TABLE STATUS WHERE Name="INTROSPECT_TEST"')
result = cursor.fetchone()
cursor.execute('DROP TABLE INTROSPECT_TEST')
return result[1] != 'MyISAM'
class DatabaseOperations(BaseDatabaseOperations):
compiler_module = "django.db.backends.mysql.compiler"
def date_extract_sql(self, lookup_type, field_name):
# http://dev.mysql.com/doc/mysql/en/date-and-time-functions.html
if lookup_type == 'week_day':
# DAYOFWEEK() returns an integer, 1-7, Sunday=1.
# Note: WEEKDAY() returns 0-6, Monday=0.
return "DAYOFWEEK(%s)" % field_name
else:
return "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
def date_trunc_sql(self, lookup_type, field_name):
fields = ['year', 'month', 'day', 'hour', 'minute', 'second']
format = ('%%Y-', '%%m', '-%%d', ' %%H:', '%%i', ':%%s') # Use double percents to escape.
format_def = ('0000-', '01', '-01', ' 00:', '00', ':00')
try:
i = fields.index(lookup_type) + 1
except ValueError:
sql = field_name
else:
format_str = ''.join([f for f in format[:i]] + [f for f in format_def[i:]])
sql = "CAST(DATE_FORMAT(%s, '%s') AS DATETIME)" % (field_name, format_str)
return sql
def date_interval_sql(self, sql, connector, timedelta):
return "(%s %s INTERVAL '%d 0:0:%d:%d' DAY_MICROSECOND)" % (sql, connector,
timedelta.days, timedelta.seconds, timedelta.microseconds)
def drop_foreignkey_sql(self):
return "DROP FOREIGN KEY"
def force_no_ordering(self):
"""
"ORDER BY NULL" prevents MySQL from implicitly ordering by grouped
columns. If no ordering would otherwise be applied, we don't want any
implicit sorting going on.
"""
return ["NULL"]
def fulltext_search_sql(self, field_name):
return 'MATCH (%s) AGAINST (%%s IN BOOLEAN MODE)' % field_name
def no_limit_value(self):
# 2**64 - 1, as recommended by the MySQL documentation
return 18446744073709551615L
def quote_name(self, name):
if name.startswith("`") and name.endswith("`"):
return name # Quoting once is enough.
return "`%s`" % name
def random_function_sql(self):
return 'RAND()'
def sql_flush(self, style, tables, sequences):
# NB: The generated SQL below is specific to MySQL
# 'TRUNCATE x;', 'TRUNCATE y;', 'TRUNCATE z;'... style SQL statements
# to clear all tables of all data
if tables:
sql = ['SET FOREIGN_KEY_CHECKS = 0;']
for table in tables:
sql.append('%s %s;' % (style.SQL_KEYWORD('TRUNCATE'), style.SQL_FIELD(self.quote_name(table))))
sql.append('SET FOREIGN_KEY_CHECKS = 1;')
# 'ALTER TABLE table AUTO_INCREMENT = 1;'... style SQL statements
# to reset sequence indices
sql.extend(["%s %s %s %s %s;" % \
(style.SQL_KEYWORD('ALTER'),
style.SQL_KEYWORD('TABLE'),
style.SQL_TABLE(self.quote_name(sequence['table'])),
style.SQL_KEYWORD('AUTO_INCREMENT'),
style.SQL_FIELD('= 1'),
) for sequence in sequences])
return sql
else:
return []
def value_to_db_datetime(self, value):
if value is None:
return None
# MySQL doesn't support tz-aware datetimes
if value.tzinfo is not None:
raise ValueError("MySQL backend does not support timezone-aware datetimes.")
# MySQL doesn't support microseconds
return unicode(value.replace(microsecond=0))
def value_to_db_time(self, value):
if value is None:
return None
# MySQL doesn't support tz-aware datetimes
if value.tzinfo is not None:
raise ValueError("MySQL backend does not support timezone-aware datetimes.")
# MySQL doesn't support microseconds
return unicode(value.replace(microsecond=0))
def year_lookup_bounds(self, value):
# Again, no microseconds
first = '%s-01-01 00:00:00'
second = '%s-12-31 23:59:59.99'
return [first % value, second % value]
def max_name_length(self):
return 64
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = 'mysql'
operators = {
'exact': '= %s',
'iexact': 'LIKE %s',
'contains': 'LIKE BINARY %s',
'icontains': 'LIKE %s',
'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',
}
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
self.server_version = None
self.features = DatabaseFeatures(self)
self.ops = DatabaseOperations()
self.client = DatabaseClient(self)
self.creation = DatabaseCreation(self)
self.introspection = DatabaseIntrospection(self)
self.validation = DatabaseValidation(self)
def _valid_connection(self):
if self.connection is not None:
try:
self.connection.ping()
return True
except DatabaseError:
self.connection.close()
self.connection = None
return False
def _cursor(self):
if not self._valid_connection():
kwargs = {
'conv': django_conversions,
'charset': 'utf8',
'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'] = 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'])
self.connection = Database.connect(**kwargs)
self.connection.encoders[SafeUnicode] = self.connection.encoders[unicode]
self.connection.encoders[SafeString] = self.connection.encoders[str]
connection_created.send(sender=self.__class__, connection=self)
cursor = CursorWrapper(self.connection.cursor())
return cursor
def _rollback(self):
try:
BaseDatabaseWrapper._rollback(self)
except Database.NotSupportedError:
pass
def get_server_version(self):
if not self.server_version:
if not self._valid_connection():
self.cursor()
m = server_version_re.match(self.connection.get_server_info())
if not m:
raise Exception('Unable to determine MySQL version from version string %r' % self.connection.get_server_info())
self.server_version = tuple([int(x) for x in m.groups()])
return self.server_version