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PostgreSQL database backend for Django.
Requires psycopg 2:
import threading
import warnings
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.db import DEFAULT_DB_ALIAS
from django.db.backends.base.base import BaseDatabaseWrapper
from django.db.utils import DatabaseError as WrappedDatabaseError
from django.utils.functional import cached_property
from django.utils.safestring import SafeText
from django.utils.version import get_version_tuple
import psycopg2 as Database
import psycopg2.extensions
import psycopg2.extras
except ImportError as e:
raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
def psycopg2_version():
version = psycopg2.__version__.split(' ', 1)[0]
return get_version_tuple(version)
PSYCOPG2_VERSION = psycopg2_version()
if PSYCOPG2_VERSION < (2, 5, 4):
raise ImproperlyConfigured("psycopg2_version 2.5.4 or newer is required; you have %s" % psycopg2.__version__)
# Some of these import psycopg2, so import them after checking if it's installed.
from .client import DatabaseClient # NOQA isort:skip
from .creation import DatabaseCreation # NOQA isort:skip
from .features import DatabaseFeatures # NOQA isort:skip
from .introspection import DatabaseIntrospection # NOQA isort:skip
from .operations import DatabaseOperations # NOQA isort:skip
from .schema import DatabaseSchemaEditor # NOQA isort:skip
from .utils import utc_tzinfo_factory # NOQA isort:skip
psycopg2.extensions.register_adapter(SafeText, psycopg2.extensions.QuotedString)
# Register support for inet[] manually so we don't have to handle the Inet()
# object on load all the time.
INETARRAY = psycopg2.extensions.new_array_type(
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = 'postgresql'
display_name = 'PostgreSQL'
# This dictionary maps Field objects to their associated PostgreSQL column
# types, as strings. Column-type strings can contain format strings; they'll
# be interpolated against the values of Field.__dict__ before being output.
# If a column type is set to None, it won't be included in the output.
data_types = {
'AutoField': 'serial',
'BigAutoField': 'bigserial',
'BinaryField': 'bytea',
'BooleanField': 'boolean',
'CharField': 'varchar(%(max_length)s)',
'DateField': 'date',
'DateTimeField': 'timestamp with time zone',
'DecimalField': 'numeric(%(max_digits)s, %(decimal_places)s)',
'DurationField': 'interval',
'FileField': 'varchar(%(max_length)s)',
'FilePathField': 'varchar(%(max_length)s)',
'FloatField': 'double precision',
'IntegerField': 'integer',
'BigIntegerField': 'bigint',
'IPAddressField': 'inet',
'GenericIPAddressField': 'inet',
'NullBooleanField': 'boolean',
'OneToOneField': 'integer',
'PositiveIntegerField': 'integer',
'PositiveSmallIntegerField': 'smallint',
'SlugField': 'varchar(%(max_length)s)',
'SmallIntegerField': 'smallint',
'TextField': 'text',
'TimeField': 'time',
'UUIDField': 'uuid',
data_type_check_constraints = {
'PositiveIntegerField': '"%(column)s" >= 0',
'PositiveSmallIntegerField': '"%(column)s" >= 0',
operators = {
'exact': '= %s',
'iexact': '= UPPER(%s)',
'contains': 'LIKE %s',
'icontains': 'LIKE UPPER(%s)',
'regex': '~ %s',
'iregex': '~* %s',
'gt': '> %s',
'gte': '>= %s',
'lt': '< %s',
'lte': '<= %s',
'startswith': 'LIKE %s',
'endswith': 'LIKE %s',
'istartswith': 'LIKE UPPER(%s)',
'iendswith': 'LIKE UPPER(%s)',
# The patterns below are used to generate SQL pattern lookup clauses when
# the right-hand side of the lookup isn't a raw string (it might be an expression
# or the result of a bilateral transformation).
# In those cases, special characters for LIKE operators (e.g. \, *, _) should be
# escaped on database side.
# Note: we use str.format() here for readability as '%' is used as a wildcard for
# the LIKE operator.
pattern_esc = r"REPLACE(REPLACE(REPLACE({}, '\', '\\'), '%%', '\%%'), '_', '\_')"
pattern_ops = {
'contains': "LIKE '%%' || {} || '%%'",
'icontains': "LIKE '%%' || UPPER({}) || '%%'",
'startswith': "LIKE {} || '%%'",
'istartswith': "LIKE UPPER({}) || '%%'",
'endswith': "LIKE '%%' || {}",
'iendswith': "LIKE '%%' || UPPER({})",
Database = Database
SchemaEditorClass = DatabaseSchemaEditor
# Classes instantiated in __init__().
client_class = DatabaseClient
creation_class = DatabaseCreation
features_class = DatabaseFeatures
introspection_class = DatabaseIntrospection
ops_class = DatabaseOperations
# PostgreSQL backend-specific attributes.
_named_cursor_idx = 0
def get_connection_params(self):
settings_dict = self.settings_dict
# None may be used to connect to the default 'postgres' db
if settings_dict['NAME'] == '':
raise ImproperlyConfigured(
"settings.DATABASES is improperly configured. "
"Please supply the NAME value.")
conn_params = {
'database': settings_dict['NAME'] or 'postgres',
conn_params.pop('isolation_level', None)
if settings_dict['USER']:
conn_params['user'] = settings_dict['USER']
if settings_dict['PASSWORD']:
conn_params['password'] = settings_dict['PASSWORD']
if settings_dict['HOST']:
conn_params['host'] = settings_dict['HOST']
if settings_dict['PORT']:
conn_params['port'] = settings_dict['PORT']
return conn_params
def get_new_connection(self, conn_params):
connection = Database.connect(**conn_params)
# self.isolation_level must be set:
# - after connecting to the database in order to obtain the database's
# default when no value is explicitly specified in options.
# - before calling _set_autocommit() because if autocommit is on, that
# will set connection.isolation_level to ISOLATION_LEVEL_AUTOCOMMIT.
options = self.settings_dict['OPTIONS']
self.isolation_level = options['isolation_level']
except KeyError:
self.isolation_level = connection.isolation_level
# Set the isolation level to the value from OPTIONS.
if self.isolation_level != connection.isolation_level:
return connection
def ensure_timezone(self):
conn_timezone_name = self.connection.get_parameter_status('TimeZone')
timezone_name = self.timezone_name
if timezone_name and conn_timezone_name != timezone_name:
with self.connection.cursor() as cursor:
cursor.execute(self.ops.set_time_zone_sql(), [timezone_name])
return True
return False
def init_connection_state(self):
timezone_changed = self.ensure_timezone()
if timezone_changed:
# Commit after setting the time zone (see #17062)
if not self.get_autocommit():
def create_cursor(self, name=None):
if name:
# In autocommit mode, the cursor will be used outside of a
# transaction, hence use a holdable cursor.
cursor = self.connection.cursor(name, scrollable=False, withhold=self.connection.autocommit)
cursor = self.connection.cursor()
cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
return cursor
def chunked_cursor(self):
self._named_cursor_idx += 1
return self._cursor(
name='_django_curs_%d_%d' % (
# Avoid reusing name in other threads
def _set_autocommit(self, autocommit):
with self.wrap_database_errors:
self.connection.autocommit = autocommit
def check_constraints(self, table_names=None):
Check constraints by setting them to immediate. Return them to deferred
self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
def is_usable(self):
# Use a psycopg cursor directly, bypassing Django's utilities.
self.connection.cursor().execute("SELECT 1")
except Database.Error:
return False
return True
def _nodb_connection(self):
nodb_connection = super()._nodb_connection
except (Database.DatabaseError, WrappedDatabaseError):
"Normally Django will use a connection to the 'postgres' database "
"to avoid running initialization queries against the production "
"database when it's not needed (for example, when running tests). "
"Django was unable to create a connection to the 'postgres' database "
"and will use the default database instead.",
settings_dict = self.settings_dict.copy()
settings_dict['NAME'] = settings.DATABASES[DEFAULT_DB_ALIAS]['NAME']
nodb_connection = self.__class__(
return nodb_connection
def pg_version(self):
with self.temporary_connection():
return self.connection.server_version