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

558 lines
22 KiB
Python

"""
MySQL database backend for Django.
Requires MySQLdb: http://sourceforge.net/projects/mysql-python
"""
from __future__ import unicode_literals
import datetime
import re
import sys
import warnings
try:
import MySQLdb as Database
except ImportError as 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, Thing2Literal
from MySQLdb.constants import FIELD_TYPE, CLIENT
try:
import pytz
except ImportError:
pytz = None
from django.conf import settings
from django.db import utils
from django.db.backends import (utils as backend_utils, BaseDatabaseFeatures,
BaseDatabaseOperations, BaseDatabaseWrapper)
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.encoding import force_str, force_text
from django.db.backends.mysql.schema import DatabaseSchemaEditor
from django.utils.functional import cached_property
from django.utils.safestring import SafeBytes, SafeText
from django.utils import six
from django.utils import timezone
# Raise exceptions for database warnings if DEBUG is on
if settings.DEBUG:
warnings.filterwarnings("error", category=Database.Warning)
DatabaseError = Database.DatabaseError
IntegrityError = Database.IntegrityError
# It's impossible to import datetime_or_None directly from MySQLdb.times
parse_datetime = conversions[FIELD_TYPE.DATETIME]
def parse_datetime_with_timezone_support(value):
dt = parse_datetime(value)
# Confirm that dt is naive before overwriting its tzinfo.
if dt is not None and settings.USE_TZ and timezone.is_naive(dt):
dt = dt.replace(tzinfo=timezone.utc)
return dt
def adapt_datetime_with_timezone_support(value, conv):
# Equivalent to DateTimeField.get_db_prep_value. Used only by raw SQL.
if settings.USE_TZ:
if timezone.is_naive(value):
warnings.warn("MySQL received a naive datetime (%s)"
" while time zone support is active." % value,
RuntimeWarning)
default_timezone = timezone.get_default_timezone()
value = timezone.make_aware(value, default_timezone)
value = value.astimezone(timezone.utc).replace(tzinfo=None)
return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S"), conv)
# 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 SafeText and SafeBytes as MySQLdb's type
# checking is too tight to catch those (see Django ticket #6052).
# Finally, MySQLdb always returns naive datetime objects. However, when
# timezone support is active, Django expects timezone-aware datetime objects.
django_conversions = conversions.copy()
django_conversions.update({
FIELD_TYPE.TIME: backend_utils.typecast_time,
FIELD_TYPE.DECIMAL: backend_utils.typecast_decimal,
FIELD_TYPE.NEWDECIMAL: backend_utils.typecast_decimal,
FIELD_TYPE.DATETIME: parse_datetime_with_timezone_support,
datetime.datetime: adapt_datetime_with_timezone_support,
})
# 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 backend_utils.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:
# args is None means no string interpolation
return self.cursor.execute(query, args)
except Database.OperationalError as e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e.args[0] in self.codes_for_integrityerror:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
raise
def executemany(self, query, args):
try:
return self.cursor.executemany(query, args)
except Database.OperationalError as e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e.args[0] in self.codes_for_integrityerror:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
raise
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
has_bulk_insert = True
has_select_for_update = True
has_select_for_update_nowait = 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
uses_savepoints = True
atomic_transactions = False
supports_check_constraints = False
def __init__(self, connection):
super(DatabaseFeatures, self).__init__(connection)
@cached_property
def _mysql_storage_engine(self):
"Internal method used in Django tests. Don't rely on this from your code"
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]
@cached_property
def can_introspect_foreign_keys(self):
"Confirm support for introspected foreign keys"
return self._mysql_storage_engine != 'MyISAM'
@cached_property
def has_zoneinfo_database(self):
# MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects
# abbreviations (eg. EAT). When pytz isn't installed and the current
# time zone is LocalTimezone (the only sensible value in this
# context), the current time zone name will be an abbreviation. As a
# consequence, MySQL cannot perform time zone conversions reliably.
if pytz is None:
return False
# Test if the time zone definitions are installed.
cursor = self.connection.cursor()
cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
return cursor.fetchone() is not None
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 datetime_extract_sql(self, lookup_type, field_name, tzname):
if settings.USE_TZ:
field_name = "CONVERT_TZ(%s, 'UTC', %%s)" % field_name
params = [tzname]
else:
params = []
# 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.
sql = "DAYOFWEEK(%s)" % field_name
else:
sql = "EXTRACT(%s FROM %s)" % (lookup_type.upper(), field_name)
return sql, params
def datetime_trunc_sql(self, lookup_type, field_name, tzname):
if settings.USE_TZ:
field_name = "CONVERT_TZ(%s, 'UTC', %%s)" % field_name
params = [tzname]
else:
params = []
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, params
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 last_executed_query(self, cursor, sql, params):
# With MySQLdb, cursor objects have an (undocumented) "_last_executed"
# attribute where the exact query sent to the database is saved.
# See MySQLdb/cursors.py in the source distribution.
return force_text(getattr(cursor, '_last_executed', None), errors='replace')
def no_limit_value(self):
# 2**64 - 1, as recommended by the MySQL documentation
return 18446744073709551615
def quote_name(self, name):
if name.startswith("`") and name.endswith("`"):
return name # Quoting once is enough.
return "`%s`" % name
def quote_parameter(self, value):
# Inner import to allow module to fail to load gracefully
import MySQLdb.converters
return MySQLdb.escape(value, MySQLdb.converters.conversions)
def random_function_sql(self):
return 'RAND()'
def sql_flush(self, style, tables, sequences, allow_cascade=False):
# 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;')
sql.extend(self.sequence_reset_by_name_sql(style, sequences))
return sql
else:
return []
def sequence_reset_by_name_sql(self, style, sequences):
# Truncate already resets the AUTO_INCREMENT field from
# MySQL version 5.0.13 onwards. Refs #16961.
if self.connection.mysql_version < (5, 0, 13):
return ["%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]
else:
return []
def validate_autopk_value(self, value):
# MySQLism: zero in AUTO_INCREMENT field does not work. Refs #17653.
if value == 0:
raise ValueError('The database backend does not accept 0 as a '
'value for AutoField.')
return value
def value_to_db_datetime(self, value):
if value is None:
return None
# MySQL doesn't support tz-aware datetimes
if timezone.is_aware(value):
if settings.USE_TZ:
value = value.astimezone(timezone.utc).replace(tzinfo=None)
else:
raise ValueError("MySQL backend does not support timezone-aware datetimes when USE_TZ is False.")
# MySQL doesn't support microseconds
return six.text_type(value.replace(microsecond=0))
def value_to_db_time(self, value):
if value is None:
return None
# MySQL doesn't support tz-aware times
if timezone.is_aware(value):
raise ValueError("MySQL backend does not support timezone-aware times.")
# MySQL doesn't support microseconds
return six.text_type(value.replace(microsecond=0))
def year_lookup_bounds_for_datetime_field(self, value):
# Again, no microseconds
first, second = super(DatabaseOperations, self).year_lookup_bounds_for_datetime_field(value)
return [first.replace(microsecond=0), second.replace(microsecond=0)]
def max_name_length(self):
return 64
def bulk_insert_sql(self, fields, num_values):
items_sql = "(%s)" % ", ".join(["%s"] * len(fields))
return "VALUES " + ", ".join([items_sql] * num_values)
def combine_expression(self, connector, sub_expressions):
"""
MySQL requires special cases for ^ operators in query expressions
"""
if connector == '^':
return 'POW(%s)' % ','.join(sub_expressions)
return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
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',
}
Database = Database
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):
cursor = self.connection.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')
cursor.close()
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):
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 schema_editor(self, *args, **kwargs):
"Returns a new instance of this backend's SchemaEditor"
return DatabaseSchemaEditor(self, *args, **kwargs)
def is_usable(self):
try:
self.connection.ping()
except DatabaseError:
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())