""" 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, 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 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 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 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 cursor._last_executed 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) 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 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. """ self.cursor().execute('SET foreign_key_checks=1') 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.get_table_list(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))