377 lines
15 KiB
Python
377 lines
15 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 warnings
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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
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from django.db.backends.base.base import BaseDatabaseWrapper
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from django.utils.encoding import force_str
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from django.db.backends.mysql.schema import DatabaseSchemaEditor
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from django.utils import six, timezone
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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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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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from MySQLdb.converters import conversions, Thing2Literal
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from MySQLdb.constants import FIELD_TYPE, CLIENT
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# Some of these import MySQLdb, so import them after checking if it's installed.
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from .client import DatabaseClient
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from .creation import DatabaseCreation
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from .features import DatabaseFeatures
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from .introspection import DatabaseIntrospection
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from .operations import DatabaseOperations
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from .validation import DatabaseValidation
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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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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 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',
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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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# The patterns below are used to generate SQL pattern lookup clauses when
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# the right-hand side of the lookup isn't a raw string (it might be an expression
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# or the result of a bilateral transformation).
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# In those cases, special characters for LIKE operators (e.g. \, *, _) should be
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# escaped on database side.
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#
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# Note: we use str.format() here for readability as '%' is used as a wildcard for
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# the LIKE operator.
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pattern_esc = r"REPLACE(REPLACE(REPLACE({}, '\\', '\\\\'), '%%', '\%%'), '_', '\_')"
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pattern_ops = {
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'contains': "LIKE BINARY CONCAT('%%', {}, '%%')",
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'icontains': "LIKE CONCAT('%%', {}, '%%')",
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'startswith': "LIKE BINARY CONCAT({}, '%%')",
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'istartswith': "LIKE CONCAT({}, '%%')",
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'endswith': "LIKE BINARY CONCAT('%%', {})",
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'iendswith': "LIKE CONCAT('%%', {})",
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}
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Database = Database
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SchemaEditorClass = DatabaseSchemaEditor
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def __init__(self, *args, **kwargs):
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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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 get_connection_params(self):
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kwargs = {
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'conv': django_conversions,
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'charset': 'utf8',
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}
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if six.PY2:
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kwargs['use_unicode'] = True
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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'] = force_str(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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return kwargs
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def get_new_connection(self, conn_params):
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conn = Database.connect(**conn_params)
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conn.encoders[SafeText] = conn.encoders[six.text_type]
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conn.encoders[SafeBytes] = conn.encoders[bytes]
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return conn
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def init_connection_state(self):
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with self.cursor() as cursor:
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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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def create_cursor(self):
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cursor = self.connection.cursor()
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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 _set_autocommit(self, autocommit):
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with self.wrap_database_errors:
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self.connection.autocommit(autocommit)
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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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# Override needs_rollback in case constraint_checks_disabled is
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# nested inside transaction.atomic.
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self.needs_rollback, needs_rollback = False, self.needs_rollback
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try:
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self.cursor().execute('SET foreign_key_checks=1')
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finally:
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self.needs_rollback = needs_rollback
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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
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key references. This method is intended to be used in conjunction with
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`disable_constraint_checking()` and `enable_constraint_checking()`, to
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determine if rows with invalid references were entered while constraint
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checks were off.
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Raises an IntegrityError on the first invalid foreign key reference
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encountered (if any) and provides detailed information about the
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invalid reference in the error message.
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Backends can override this method if they can more directly apply
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constraint checking (e.g. via "SET CONSTRAINTS 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.table_names(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"""
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% (primary_key_column_name, column_name, table_name, referenced_table_name,
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column_name, referenced_column_name, column_name, referenced_column_name))
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for bad_row in cursor.fetchall():
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raise utils.IntegrityError("The row in table '%s' with primary key '%s' has an invalid "
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"foreign key: %s.%s contains a value '%s' that does not have a corresponding value in %s.%s."
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% (table_name, bad_row[0],
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table_name, column_name, bad_row[1],
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referenced_table_name, referenced_column_name))
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def is_usable(self):
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try:
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self.connection.ping()
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except Database.Error:
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return False
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else:
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return True
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@cached_property
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def mysql_version(self):
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with self.temporary_connection():
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server_info = self.connection.get_server_info()
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match = server_version_re.match(server_info)
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if not match:
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raise Exception('Unable to determine MySQL version from version string %r' % server_info)
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return tuple(int(x) for x in match.groups())
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