Fix a bug in the improved version of get_foreign_field.

modules/plugin_dbui/helper.py

@@ -242,16 +242,14 @@ def get_foreign_field(field):
     # IS_IN_DB is not use. 
     # The parent key for the left join is the id key of the parent table
     # the parent field is the first field of the parent table which differs id
-    if not validators:
-        i = field.type.index(' ')
-        ktablename = field.type[i:].strip()
-        
-        for kfield in field._db[ktablename]:
-            if kfield.name != 'id':
-                return (ktablename, kfield.name, 'id')
-            
+    i = field.type.index(' ')
+    ktablename = field.type[i:].strip()
+    
+    for kfield in field._db[ktablename]:
+        if kfield.name != 'id':
+            return (ktablename, kfield.name, 'id')
 
-    return None
+    raise Exception
 
 
 def get_id(table, **kwargs):