303 lines
12 KiB
Python
303 lines
12 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 re
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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, FLAG, CLIENT
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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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# 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 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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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 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.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 Database.IntegrityError(tuple(e))
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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, 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 Database.IntegrityError(tuple(e))
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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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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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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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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 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 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 value.tzinfo is not None:
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raise ValueError("MySQL backend does not support timezone-aware datetimes.")
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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 datetimes
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if value.tzinfo is not None:
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raise ValueError("MySQL backend does not support timezone-aware datetimes.")
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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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class DatabaseWrapper(BaseDatabaseWrapper):
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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()
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self.ops = DatabaseOperations()
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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()
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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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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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settings_dict = self.settings_dict
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if settings_dict['DATABASE_USER']:
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kwargs['user'] = settings_dict['DATABASE_USER']
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if settings_dict['DATABASE_NAME']:
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kwargs['db'] = settings_dict['DATABASE_NAME']
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if settings_dict['DATABASE_PASSWORD']:
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kwargs['passwd'] = settings_dict['DATABASE_PASSWORD']
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if settings_dict['DATABASE_HOST'].startswith('/'):
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kwargs['unix_socket'] = settings_dict['DATABASE_HOST']
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elif settings_dict['DATABASE_HOST']:
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kwargs['host'] = settings_dict['DATABASE_HOST']
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if settings_dict['DATABASE_PORT']:
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kwargs['port'] = int(settings_dict['DATABASE_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['DATABASE_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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connection_created.send(sender=self.__class__)
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cursor = CursorWrapper(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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