magic-removal: Added 'dummy' database backend, which is used as a fallback if DATABASE_ENGINE isn't set

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@1803 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/__init__.py

@@ -3,8 +3,7 @@ from django.conf.settings import DATABASE_ENGINE
 __all__ = ('backend', 'connection', 'DatabaseError')
 
 if not DATABASE_ENGINE:
-    from django.core.exceptions import ImproperlyConfigured
+    DATABASE_ENGINE = 'dummy'
-    raise ImproperlyConfigured, "You haven't set the DATABASE_ENGINE setting yet."
 
 try:
     backend = __import__('django.db.backends.%s.base' % DATABASE_ENGINE, '', '', [''])

django/db/backends/dummy/base.py

@@ -0,0 +1,36 @@
+"""
+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
+
+def complain(*args, **kwargs):
+    raise ImproperlyConfigured, "You haven't set the DATABASE_ENGINE setting yet."
+
+class DatabaseError(Exception):
+    pass
+
+class DatabaseWrapper:
+    cursor = complain
+    commit = complain
+    rollback = complain
+
+    def close(self):
+        pass # close()
+
+supports_constraints = False
+quote_name = complain
+dictfetchone = complain
+dictfetchmany = complain
+dictfetchall = complain
+get_last_insert_id = complain
+get_date_extract_sql = complain
+get_date_trunc_sql = complain
+get_limit_offset_sql = complain
+get_random_function_sql = complain
+OPERATOR_MAPPING = {}

django/db/backends/dummy/creation.py

@@ -0,0 +1 @@
+DATA_TYPES = {}

django/db/backends/dummy/introspection.py

@@ -0,0 +1,7 @@
+from django.db.backends.dummy.base import complain
+
+get_table_list = complain
+get_table_description = complain
+get_relations = complain
+
+DATA_TYPES_REVERSE = {}