Add window functions on Database

issue6355
review33961002

CHANGELOG

@@ -1,3 +1,4 @@
+* Add has_window_functions on Database
 * Allow Many2One on ModelSQL to target ModelStorage
 * Manage Cache in Transaction
 * Allow to register multiple exit functions on Transaction

trytond/backend/database.py

@@ -155,3 +155,7 @@ class DatabaseInterface(object):
     def has_select_for(self):
         "Return if database supports FOR UPDATE/SHARE clause in SELECT."
         return False
+
+    def has_window_functions(self):
+        "Return if database supports window functions."
+        return False

trytond/backend/postgresql/database.py

@@ -304,6 +304,9 @@ class Database(DatabaseInterface):
     def has_select_for(self):
         return True
 
+    def has_window_functions(self):
+        return True
+
 register_type(UNICODE)
 if PYDATE:
     register_type(PYDATE)