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"""
PostgreSQL database backend for Django.
Requires psycopg 2: http://initd.org/projects/psycopg2
"""
from django.conf import settings
from django.db.backends.base.base import BaseDatabaseWrapper
from django.db.backends.base.validation import BaseDatabaseValidation
from django.utils.encoding import force_str
from django.utils.functional import cached_property
from django.utils.safestring import SafeText, SafeBytes
try:
import psycopg2 as Database
import psycopg2.extensions
import psycopg2.extras
except ImportError as e:
from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
# Some of these import psycopg2, so import them after checking if it's installed.
from .client import DatabaseClient
from .creation import DatabaseCreation
from .features import DatabaseFeatures
from .introspection import DatabaseIntrospection
from .operations import DatabaseOperations
from .schema import DatabaseSchemaEditor
from .utils import utc_tzinfo_factory
from .version import get_version
DatabaseError = Database.DatabaseError
IntegrityError = Database.IntegrityError
psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
psycopg2.extensions.register_type(psycopg2.extensions.UNICODEARRAY)
psycopg2.extensions.register_adapter(SafeBytes, psycopg2.extensions.QuotedString)
psycopg2.extensions.register_adapter(SafeText, psycopg2.extensions.QuotedString)
psycopg2.extras.register_uuid()
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = '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',
'BinaryField': 'bytea',
'BooleanField': 'boolean',
'CharField': 'varchar(%(max_length)s)',
'CommaSeparatedIntegerField': '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
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
opts = self.settings_dict["OPTIONS"]
RC = psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED
self.isolation_level = opts.get('isolation_level', RC)
self.features = DatabaseFeatures(self)
self.ops = DatabaseOperations(self)
self.client = DatabaseClient(self)
self.creation = DatabaseCreation(self)
self.introspection = DatabaseIntrospection(self)
self.validation = BaseDatabaseValidation(self)
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'] == '':
from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured(
"settings.DATABASES is improperly configured. "
"Please supply the NAME value.")
conn_params = {
'database': settings_dict['NAME'] or 'postgres',
}
conn_params.update(settings_dict['OPTIONS'])
if 'autocommit' in conn_params:
del conn_params['autocommit']
if 'isolation_level' in conn_params:
del conn_params['isolation_level']
if settings_dict['USER']:
conn_params['user'] = settings_dict['USER']
if settings_dict['PASSWORD']:
conn_params['password'] = force_str(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):
return Database.connect(**conn_params)
def init_connection_state(self):
settings_dict = self.settings_dict
self.connection.set_client_encoding('UTF8')
tz = 'UTC' if settings.USE_TZ else settings_dict.get('TIME_ZONE')
if tz:
try:
get_parameter_status = self.connection.get_parameter_status
except AttributeError:
# psycopg2 < 2.0.12 doesn't have get_parameter_status
conn_tz = None
else:
conn_tz = get_parameter_status('TimeZone')
if conn_tz != tz:
cursor = self.connection.cursor()
try:
cursor.execute(self.ops.set_time_zone_sql(), [tz])
finally:
cursor.close()
# Commit after setting the time zone (see #17062)
if not self.get_autocommit():
self.connection.commit()
def create_cursor(self):
cursor = self.connection.cursor()
cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
return cursor
def _set_isolation_level(self, isolation_level):
assert isolation_level in range(1, 5) # Use set_autocommit for level = 0
if self.psycopg2_version >= (2, 4, 2):
self.connection.set_session(isolation_level=isolation_level)
else:
self.connection.set_isolation_level(isolation_level)
def _set_autocommit(self, autocommit):
with self.wrap_database_errors:
if self.psycopg2_version >= (2, 4, 2):
self.connection.autocommit = autocommit
else:
if autocommit:
level = psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT
else:
level = self.isolation_level
self.connection.set_isolation_level(level)
def check_constraints(self, table_names=None):
"""
To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they
are returned to deferred.
"""
self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
def is_usable(self):
try:
# Use a psycopg cursor directly, bypassing Django's utilities.
self.connection.cursor().execute("SELECT 1")
except Database.Error:
return False
else:
return True
@cached_property
def psycopg2_version(self):
version = psycopg2.__version__.split(' ', 1)[0]
return tuple(int(v) for v in version.split('.') if v.isdigit())
@cached_property
def pg_version(self):
with self.temporary_connection():
return get_version(self.connection)
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