"""

Dummy database backend for Django.

Django uses this if the DATABASE_ENGINE setting is empty (None or empty string).

Each of these API functions, except connection.close(), raises

ImproperlyConfigured.

"""

from django.core.exceptions import ImproperlyConfigured

from django.db.backends import *

from django.db.backends.creation import BaseDatabaseCreation

def complain(*args, **kwargs):

    raise ImproperlyConfigured, "You haven't set the DATABASE_ENGINE setting yet."

def ignore(*args, **kwargs):

    pass

class DatabaseError(Exception):

    pass

class IntegrityError(DatabaseError):

    pass

class DatabaseOperations(BaseDatabaseOperations):

    quote_name = complain

class DatabaseClient(BaseDatabaseClient):

    runshell = complain

class DatabaseIntrospection(BaseDatabaseIntrospection):

    get_table_list = complain

    get_table_description = complain

    get_relations = complain

    get_indexes = complain

class DatabaseWrapper(object):    

    operators = {}

    cursor = complain

    _commit = complain

    _rollback = ignore

    def __init__(self, *args, **kwargs):

        super(DatabaseWrapper, self).__init__(*args, **kwargs)

        self.features = BaseDatabaseFeatures()

        self.ops = DatabaseOperations()

        self.client = DatabaseClient()

        self.creation = BaseDatabaseCreation(self)

        self.introspection = DatabaseIntrospection(self)

        self.validation = BaseDatabaseValidation()

    def close(self):

        pass