Refactored get_random_function_sql() to DatabaseOperations.random_function_sql(). Refs #5106

git-svn-id: http://code.djangoproject.com/svn/django/trunk@5962 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/backends/__init__.py

@@ -133,3 +133,9 @@ class BaseDatabaseOperations(object):
         the field should use its default value.
         """
         return 'DEFAULT'
+
+    def random_function_sql(self):
+        """
+        Returns a SQL expression that returns a random value.
+        """
+        return 'RANDOM()'

django/db/backends/ado_mssql/base.py

@@ -67,6 +67,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         cursor.execute("SELECT %s FROM %s WHERE %s = @@IDENTITY" % (pk_name, table_name, pk_name))
         return cursor.fetchone()[0]
 
+    def random_function_sql(self):
+        return 'RAND()'
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -100,9 +103,6 @@ dictfetchone = util.dictfetchone
 dictfetchmany = util.dictfetchmany
 dictfetchall  = util.dictfetchall
 
-def get_random_function_sql():
-    return "RAND()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/backends/dummy/base.py

@@ -43,7 +43,6 @@ quote_name = complain
 dictfetchone = complain
 dictfetchmany = complain
 dictfetchall = complain
-get_random_function_sql = complain
 get_start_transaction_sql = complain
 get_sql_flush = complain
 get_sql_sequence_reset = complain

django/db/backends/mysql/base.py

@@ -84,6 +84,9 @@ class DatabaseOperations(BaseDatabaseOperations):
             sql += "%s," % offset
         return sql + str(limit)
 
+    def random_function_sql(self):
+        return 'RAND()'
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -162,9 +165,6 @@ dictfetchone = util.dictfetchone
 dictfetchmany = util.dictfetchmany
 dictfetchall  = util.dictfetchall
 
-def get_random_function_sql():
-    return "RAND()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/backends/mysql_old/base.py

@@ -94,6 +94,9 @@ class DatabaseOperations(BaseDatabaseOperations):
             sql += "%s," % offset
         return sql + str(limit)
 
+    def random_function_sql(self):
+        return 'RAND()'
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -181,9 +184,6 @@ dictfetchone = util.dictfetchone
 dictfetchmany = util.dictfetchmany
 dictfetchall  = util.dictfetchall
 
-def get_random_function_sql():
-    return "RAND()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/backends/oracle/base.py

@@ -70,6 +70,9 @@ class DatabaseOperations(BaseDatabaseOperations):
     def max_name_length(self):
         return 30
 
+    def random_function_sql(self):
+        return "DBMS_RANDOM.RANDOM"
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -186,9 +189,6 @@ def get_field_cast_sql(db_type):
     else:
         return "%s%s"
 
-def get_random_function_sql():
-    return "DBMS_RANDOM.RANDOM"
-
 def get_start_transaction_sql():
     return None
 
@@ -380,7 +380,7 @@ def get_query_set_class(DefaultQuerySet):
                 ordering_to_use = opts.ordering
             for f in handle_legacy_orderlist(ordering_to_use):
                 if f == '?': # Special case.
-                    order_by.append(backend.get_random_function_sql())
+                    order_by.append(DatabaseOperations().random_function_sql())
                 else:
                     if f.startswith('-'):
                         col_name = f[1:]

django/db/backends/postgresql/base.py

@@ -131,9 +131,6 @@ def dictfetchall(cursor):
     "Returns all rows from a cursor as a dict"
     return cursor.dictfetchall()
 
-def get_random_function_sql():
-    return "RANDOM()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/backends/postgresql_psycopg2/base.py

@@ -85,9 +85,6 @@ dictfetchone = util.dictfetchone
 dictfetchmany = util.dictfetchmany
 dictfetchall = util.dictfetchall
 
-def get_random_function_sql():
-    return "RANDOM()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/backends/sqlite3/base.py

@@ -118,9 +118,6 @@ def _sqlite_extract(lookup_type, dt):
         return None
     return str(getattr(dt, lookup_type))
 
-def get_random_function_sql():
-    return "RANDOM()"
-
 def get_start_transaction_sql():
     return "BEGIN;"
 

django/db/models/query.py

@@ -71,7 +71,7 @@ def orderlist2sql(order_list, opts, prefix=''):
         if f.startswith('-'):
             output.append('%s%s DESC' % (prefix, backend.quote_name(orderfield2column(f[1:], opts))))
         elif f == '?':
-            output.append(backend.get_random_function_sql())
+            output.append(connection.ops.random_function_sql())
         else:
             output.append('%s%s ASC' % (prefix, backend.quote_name(orderfield2column(f, opts))))
     return ', '.join(output)
@@ -531,7 +531,7 @@ class _QuerySet(object):
             ordering_to_use = opts.ordering
         for f in handle_legacy_orderlist(ordering_to_use):
             if f == '?': # Special case.
-                order_by.append(backend.get_random_function_sql())
+                order_by.append(connection.ops.random_function_sql())
             else:
                 if f.startswith('-'):
                     col_name = f[1:]