207 lines
7.9 KiB
Python
207 lines
7.9 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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from django.db.backends import BaseDatabaseWrapper, BaseDatabaseFeatures, BaseDatabaseOperations, util
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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
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from MySQLdb.constants import FIELD_TYPE
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import re
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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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# MySQLdb-1.2.1 supports the Python boolean type, and only uses datetime
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# module for time-related columns; older versions could have used mx.DateTime
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# or strings if there were no datetime module. However, MySQLdb still returns
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# TIME columns as timedelta -- they are more like timedelta in terms of actual
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# behavior as they are signed and include days -- and Django expects time, so
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# we still need to override that.
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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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})
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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 DatabaseFeatures(BaseDatabaseFeatures):
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autoindexes_primary_keys = False
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inline_fk_references = False
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empty_fetchmany_value = ()
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update_can_self_select = False
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class DatabaseOperations(BaseDatabaseOperations):
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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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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 drop_foreignkey_sql(self):
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return "DROP FOREIGN KEY"
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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 limit_offset_sql(self, limit, offset=None):
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# 'LIMIT 20,40'
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sql = "LIMIT "
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if offset and offset != 0:
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sql += "%s," % offset
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return sql + str(limit)
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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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class DatabaseWrapper(BaseDatabaseWrapper):
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features = DatabaseFeatures()
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ops = DatabaseOperations()
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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, **kwargs):
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super(DatabaseWrapper, self).__init__(**kwargs)
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self.server_version = None
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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, settings):
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if not self._valid_connection():
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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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if settings.DATABASE_USER:
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kwargs['user'] = settings.DATABASE_USER
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if settings.DATABASE_NAME:
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kwargs['db'] = settings.DATABASE_NAME
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if settings.DATABASE_PASSWORD:
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kwargs['passwd'] = settings.DATABASE_PASSWORD
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if settings.DATABASE_HOST.startswith('/'):
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kwargs['unix_socket'] = settings.DATABASE_HOST
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elif settings.DATABASE_HOST:
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kwargs['host'] = settings.DATABASE_HOST
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if settings.DATABASE_PORT:
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kwargs['port'] = int(settings.DATABASE_PORT)
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kwargs.update(self.options)
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self.connection = Database.connect(**kwargs)
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cursor = self.connection.cursor()
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return 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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