249 lines
9.7 KiB
Python
249 lines
9.7 KiB
Python
"""
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PostgreSQL database backend for Django.
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Requires psycopg 2: http://initd.org/projects/psycopg2
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"""
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import sys
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from django.db import utils
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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.postgresql_psycopg2.operations import DatabaseOperations
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from django.db.backends.postgresql_psycopg2.client import DatabaseClient
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from django.db.backends.postgresql_psycopg2.creation import DatabaseCreation
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from django.db.backends.postgresql_psycopg2.version import get_version
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from django.db.backends.postgresql_psycopg2.introspection import DatabaseIntrospection
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from django.db.backends.postgresql_psycopg2.schema import DatabaseSchemaEditor
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from django.utils.encoding import force_str
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from django.utils.log import getLogger
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from django.utils.safestring import SafeText, SafeBytes
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from django.utils import six
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from django.utils.timezone import utc
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try:
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import psycopg2 as Database
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import psycopg2.extensions
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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 psycopg2 module: %s" % e)
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
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psycopg2.extensions.register_adapter(SafeBytes, psycopg2.extensions.QuotedString)
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psycopg2.extensions.register_adapter(SafeText, psycopg2.extensions.QuotedString)
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logger = getLogger('django.db.backends')
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def utc_tzinfo_factory(offset):
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if offset != 0:
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raise AssertionError("database connection isn't set to UTC")
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return utc
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class CursorWrapper(object):
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"""
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A thin wrapper around psycopg2'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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"""
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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.IntegrityError as e:
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six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
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except Database.DatabaseError as e:
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six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
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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.IntegrityError as e:
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six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
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except Database.DatabaseError as e:
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six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
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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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needs_datetime_string_cast = False
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can_return_id_from_insert = True
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requires_rollback_on_dirty_transaction = True
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has_real_datatype = True
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can_defer_constraint_checks = True
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has_select_for_update = True
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has_select_for_update_nowait = True
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has_bulk_insert = True
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supports_tablespaces = True
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can_distinct_on_fields = True
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can_rollback_ddl = True
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supports_combined_alters = True
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'postgresql'
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operators = {
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'exact': '= %s',
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'iexact': '= UPPER(%s)',
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'contains': 'LIKE %s',
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'icontains': 'LIKE UPPER(%s)',
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'regex': '~ %s',
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'iregex': '~* %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 %s',
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'endswith': 'LIKE %s',
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'istartswith': 'LIKE UPPER(%s)',
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'iendswith': 'LIKE UPPER(%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.features = DatabaseFeatures(self)
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autocommit = self.settings_dict["OPTIONS"].get('autocommit', False)
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self.features.uses_autocommit = autocommit
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if autocommit:
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level = psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT
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else:
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level = psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED
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self._set_isolation_level(level)
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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 = BaseDatabaseValidation(self)
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self._pg_version = None
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def check_constraints(self, table_names=None):
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"""
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To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they
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are returned to deferred.
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"""
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self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
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self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
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def close(self):
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self.validate_thread_sharing()
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if self.connection is None:
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return
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try:
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self.connection.close()
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self.connection = None
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except Database.Error:
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# In some cases (database restart, network connection lost etc...)
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# the connection to the database is lost without giving Django a
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# notification. If we don't set self.connection to None, the error
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# will occur a every request.
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self.connection = None
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logger.warning('psycopg2 error while closing the connection.',
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exc_info=sys.exc_info()
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)
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raise
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def _get_pg_version(self):
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if self._pg_version is None:
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self._pg_version = get_version(self.connection)
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return self._pg_version
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pg_version = property(_get_pg_version)
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def _cursor(self):
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settings_dict = self.settings_dict
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if self.connection is None:
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if not settings_dict['NAME']:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured(
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"settings.DATABASES is improperly configured. "
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"Please supply the NAME value.")
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conn_params = {
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'database': settings_dict['NAME'],
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}
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conn_params.update(settings_dict['OPTIONS'])
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if 'autocommit' in conn_params:
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del conn_params['autocommit']
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if settings_dict['USER']:
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conn_params['user'] = settings_dict['USER']
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if settings_dict['PASSWORD']:
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conn_params['password'] = force_str(settings_dict['PASSWORD'])
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if settings_dict['HOST']:
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conn_params['host'] = settings_dict['HOST']
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if settings_dict['PORT']:
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conn_params['port'] = settings_dict['PORT']
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self.connection = Database.connect(**conn_params)
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self.connection.set_client_encoding('UTF8')
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tz = 'UTC' if settings.USE_TZ else settings_dict.get('TIME_ZONE')
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if tz:
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try:
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get_parameter_status = self.connection.get_parameter_status
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except AttributeError:
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# psycopg2 < 2.0.12 doesn't have get_parameter_status
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conn_tz = None
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else:
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conn_tz = get_parameter_status('TimeZone')
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if conn_tz != tz:
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# Set the time zone in autocommit mode (see #17062)
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self.connection.set_isolation_level(
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psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
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self.connection.cursor().execute(
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self.ops.set_time_zone_sql(), [tz])
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self.connection.set_isolation_level(self.isolation_level)
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self._get_pg_version()
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connection_created.send(sender=self.__class__, connection=self)
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cursor = self.connection.cursor()
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cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
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return CursorWrapper(cursor)
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def _enter_transaction_management(self, managed):
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"""
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Switch the isolation level when needing transaction support, so that
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the same transaction is visible across all the queries.
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"""
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if self.features.uses_autocommit and managed and not self.isolation_level:
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self._set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED)
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def _leave_transaction_management(self, managed):
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"""
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If the normal operating mode is "autocommit", switch back to that when
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leaving transaction management.
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"""
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if self.features.uses_autocommit and not managed and self.isolation_level:
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self._set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
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def _set_isolation_level(self, level):
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"""
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Do all the related feature configurations for changing isolation
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levels. This doesn't touch the uses_autocommit feature, since that
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controls the movement *between* isolation levels.
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"""
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assert level in range(5)
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try:
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if self.connection is not None:
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self.connection.set_isolation_level(level)
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finally:
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self.isolation_level = level
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self.features.uses_savepoints = bool(level)
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def _commit(self):
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if self.connection is not None:
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try:
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return self.connection.commit()
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except Database.IntegrityError as e:
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six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
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def schema_editor(self):
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"Returns a new instance of this backend's SchemaEditor"
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return DatabaseSchemaEditor(self)
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