diff --git a/openerp/osv/fields.py b/openerp/osv/fields.py
index 34968a662fb..8591346471c 100644
--- a/openerp/osv/fields.py
+++ b/openerp/osv/fields.py
@@ -1067,6 +1067,8 @@ class function(_column):
             self._classic_write = True
             if type=='binary':
                 self._symbol_get=lambda x:x and str(x)
+            else:
+                self._prefetch = True
 
         if type == 'float':
             self._symbol_c = float._symbol_c
diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 870efd3dd8b..499a21f8555 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -385,11 +385,11 @@ class browse_record(object):
             # if the field is a classic one or a many2one, we'll fetch all classic and many2one fields
             if col._prefetch:
                 # gen the list of "local" (ie not inherited) fields which are classic or many2one
-                fields_to_fetch = filter(lambda x: x[1]._classic_write, self._table._columns.items())
+                fields_to_fetch = filter(lambda x: x[1]._classic_write and x[1]._prefetch, self._table._columns.items())
                 # gen the list of inherited fields
                 inherits = map(lambda x: (x[0], x[1][2]), self._table._inherit_fields.items())
                 # complete the field list with the inherited fields which are classic or many2one
-                fields_to_fetch += filter(lambda x: x[1]._classic_write, inherits)
+                fields_to_fetch += filter(lambda x: x[1]._classic_write and x[1]._prefetch, inherits)
             # otherwise we fetch only that field
             else:
                 fields_to_fetch = [(name, col)]