# STI and acts\_as\_list: scope =\> type does not work? **URL:** \ **Category:** Rails\ **Created:** [December 16, 2006, 12:20pm UTC](https://www.ruby-forum.com/t/sti-and-acts-as-list-scope-type-does-not-work/79555 "2006-12-16T12:20:09Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![josh](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/45deac/32.png) [@josh](https://www.ruby-forum.com/u/josh)\ **Post date:** [December 16, 2006, 12:20pm UTC](https://www.ruby-forum.com/t/sti-and-acts-as-list-scope-type-does-not-work/79555/1 "2006-12-16T12:20:09Z")
Hi all I have a model Product1 and Product2 which both have Product as parent class. I use single table inheritance to share their similar DB fields. Now I wanted to add acts\_as\_list for them, and wanted to use :scope =\> :type so the position numbers are not shared between Product1 and Product2 but every Class has its own order. Sadly when adding a new Product1 or Product2 I get the following error: NameError in UnikateController#manage undefined local variable or method `type\_id’ for #Product1:0x25a5270 Why does Rails append an “\_id” suffix to type? Is it not possible to use “type” only? Thanks. Josh ---
**Author:** ![josh](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/45deac/32.png) [@josh](https://www.ruby-forum.com/u/josh)\ **Post date:** [December 16, 2006, 12:23pm UTC](https://www.ruby-forum.com/t/sti-and-acts-as-list-scope-type-does-not-work/79555/2 "2006-12-16T12:23:14Z")
Well got it myself already. Rails API: scope - restricts what is to be considered a list. Given a symbol, it’ll attach “\_id” (if that hasn’t been already) and use that as the foreign key restriction. So I’m using a string now instead of a symbol, and it works. Quite strange behavior though, is this consistently used throughout Rails? “Symbols can be modified by Rails, strings are taken as-is”?