[soc2010/query-refactor] Altered the base database backend class to not have anything more than the bare minimum. Also add the bare beginnings for a mongodb backend.

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2010/query-refactor@13330 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/mongodb/README

@@ -0,0 +1,5 @@
+NOTE
+====
+
+This backend lives here for conveinience purposes during the 2010 GSOC.  This
+is not it's permanent location (nor should you probably be using it all).

django/contrib/mongodb/base.py

@@ -0,0 +1,5 @@
+from django.db.backends import BaseDatabaseWrapper
+
+
+class DatabaseWrapper(BaseDatabaseWrapper):
+    pass

django/db/backends/__init__.py

@@ -10,13 +10,10 @@ class BaseDatabaseWrapper(local):
     """
     Represents a database connection.
     """
-    ops = None
-
     def __init__(self, settings_dict, alias=DEFAULT_DB_ALIAS):
         # `settings_dict` should be a dictionary containing keys such as
         # NAME, USER, etc. It's called `settings_dict` instead of `settings`
         # to disambiguate it from Django settings modules.
-        self.connection = None
         self.queries = []
         self.settings_dict = settings_dict
         self.alias = alias
@@ -27,6 +24,14 @@ class BaseDatabaseWrapper(local):
     def __ne__(self, other):
         return not self == other
 
+
+class BaseSQLDatabaseWrapper(BaseDatabaseWrapper):
+    ops = None
+    
+    def __init__(self, *args, **kwargs):
+        self.connection = None
+        super(BaseSQLDatabaseWrapper, self).__init__(*args, **kwargs)
+
     def _commit(self):
         if self.connection is not None:
             return self.connection.commit()
@@ -80,6 +85,7 @@ class BaseDatabaseWrapper(local):
     def make_debug_cursor(self, cursor):
         return util.CursorDebugWrapper(cursor, self)
 
+
 class BaseDatabaseFeatures(object):
     allows_group_by_pk = False
     # True if django.db.backend.utils.typecast_timestamp is used on values

django/db/backends/mysql/base.py

@@ -230,7 +230,7 @@ class DatabaseOperations(BaseDatabaseOperations):
     def max_name_length(self):
         return 64
 
-class DatabaseWrapper(BaseDatabaseWrapper):
+class DatabaseWrapper(BaseSQLDatabaseWrapper):
 
     operators = {
         'exact': '= %s',
@@ -303,7 +303,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
     def _rollback(self):
         try:
-            BaseDatabaseWrapper._rollback(self)
+            super(DatabaseWrapper, self)._rollback()
         except Database.NotSupportedError:
             pass
 

django/db/backends/oracle/base.py

@@ -310,7 +310,7 @@ WHEN (new.%(col_name)s IS NULL)
         return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
 
 
-class DatabaseWrapper(BaseDatabaseWrapper):
+class DatabaseWrapper(BaseSQLDatabaseWrapper):
 
     operators = {
         'exact': '= %s',

django/db/backends/postgresql/base.py

@@ -81,7 +81,7 @@ class UnicodeCursorWrapper(object):
 class DatabaseFeatures(BaseDatabaseFeatures):
     uses_savepoints = True
 
-class DatabaseWrapper(BaseDatabaseWrapper):
+class DatabaseWrapper(BaseSQLDatabaseWrapper):
     operators = {
         'exact': '= %s',
         'iexact': '= UPPER(%s)',

django/db/backends/postgresql_psycopg2/base.py

@@ -78,7 +78,7 @@ class DatabaseOperations(PostgresqlDatabaseOperations):
     def return_insert_id(self):
         return "RETURNING %s", ()
 
-class DatabaseWrapper(BaseDatabaseWrapper):
+class DatabaseWrapper(BaseSQLDatabaseWrapper):
     operators = {
         'exact': '= %s',
         'iexact': '= UPPER(%s)',

django/db/backends/sqlite3/base.py

@@ -128,7 +128,7 @@ class DatabaseOperations(BaseDatabaseOperations):
         # No field, or the field isn't known to be a decimal or integer
         return value
 
-class DatabaseWrapper(BaseDatabaseWrapper):
+class DatabaseWrapper(BaseSQLDatabaseWrapper):
 
     # SQLite requires LIKE statements to include an ESCAPE clause if the value
     # being escaped has a percent or underscore in it.
@@ -184,7 +184,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         # database. To prevent accidental data loss, ignore close requests on
         # an in-memory db.
         if self.settings_dict['NAME'] != ":memory:":
-            BaseDatabaseWrapper.close(self)
+            super(DatabaseWrapper, self).close()
 
 FORMAT_QMARK_REGEX = re.compile(r'(?![^%])%s')