diff --git a/trytond/osv/orm.py b/trytond/osv/orm.py
index 4bf7241b06..472cbc83f1 100644
--- a/trytond/osv/orm.py
+++ b/trytond/osv/orm.py
@@ -522,6 +522,7 @@ class ORM(object):
         self._inherit_fields = []
         self._order = [('id', 'ASC')]
         self._error_messages = {}
+        self._sql_error_messages = {}
         # reinit the cache on _columns and _defaults
         self.__columns = None
         self.__defaults = None
diff --git a/trytond/osv/osv.py b/trytond/osv/osv.py
index 9934c2c789..efd07060d3 100644
--- a/trytond/osv/osv.py
+++ b/trytond/osv/osv.py
@@ -136,6 +136,9 @@ class OSVService(Service):
             res.append(inst)
             for key, _, msg in inst._sql_constraints:
                 self._sql_errors[inst._table + '_' + key] = msg
+            for key in inst._sql_error_messages.keys():
+                self._sql_errors[inst._table + '_' + key] = \
+                        inst._sql_error_messages[key]
         return res
 
 osv_pool = OSVService