diff --git a/bin/osv/orm.py b/bin/osv/orm.py
index 208ec41e55b..147e8490fdf 100644
--- a/bin/osv/orm.py
+++ b/bin/osv/orm.py
@@ -2638,24 +2638,29 @@ class orm(orm_template):
             select = ids
         select = map(lambda x: isinstance(x,dict) and x['id'] or x, select)
         result = self._read_flat(cr, user, select, fields, context, load)
+
         for r in result:
             for key, v in r.items():
-                if v == None:
-                    r[key] = False
-                if key in self._columns.keys():
-                    type = self._columns[key]._type
-                elif key in self._inherit_fields.keys():
-                    type = self._inherit_fields[key][2]._type
+                if key in self._columns:
+                    column = self._columns[key]
+                elif key in self._inherit_fields:
+                    column = self._inherit_fields[key][2]
                 else:
                     continue
-                if type == 'reference' and v:
-                    model,ref_id = v.split(',')
-                    table = self.pool.get(model)._table
-                    cr.execute('select id from "%s" where id=%s' % (table,ref_id))
-                    id_exist = cr.fetchone()
-                    if not id_exist:
-                        cr.execute('update "'+self._table+'" set "'+key+'"=NULL where "%s"=%s' %(key,''.join("'"+str(v)+"'")))
-                        r[key] = ''
+                if v and column._type == 'reference':
+                    model_name, ref_id = v.split(',', 1)
+                    model = self.pool.get(model_name)
+                    if not model:
+                        reset = True
+                    else:
+                        cr.execute('SELECT count(1) FROM "%s" WHERE id=%%s' % (model._table,), (ref_id,))
+                        reset = not cr.fetchone()[0]
+                    if reset:
+                        if column._classic_write:
+                            query = 'UPDATE "%s" SET "%s"=NULL WHERE id=%%s' % (self._table, key)
+                            cr.execute(query, (r['id'],))
+                        r[key] = False
+
         if isinstance(ids, (int, long, dict)):
             return result and result[0] or False
         return result