I'm trying to figure out the best way to set this data model up. I'm still pretty new to Rails, but hopefully I could turn this into something useful to others as well. Here are the basics: User has_many items items are taggable (items habtm taggings, tags habtm taggings) I also want users to be able to order their tagged items. So if I've tagged 5 items as "cool" I want to be able to order them 1-5. The DB design seems straight forward: items: id user_id name, etc tags: id name taggings: tag_id message_id position But it gets hairy when trying to use ActiveRecord relationships. There are some good ideas about HABTM lists: http://wiki.rubyonrails.org/rails/pages/HowToUseAc... But easily getting that to only show messages for a particular user is not straightforward. You could hack it a bit by adding another table/model that was a TagList, with a user_id, tag_id, message_id, and position - but that seems like a lot of data duplication. That just got me thinking that maybe you can make the model for TagList, but not have it be based on an actual table (make it a composite model). I seem to remember reading about that - maybe I'm delirious - I'm off to look it up. Anyone have any thoughts on this? And please don't tell me there is some better support for this in Edge Rails. I've tried getting Edge Rails running, and it has broken me. I'll wait until 1.1 is out :)
on 2006-03-08 03:48
on 2006-03-08 04:08
To avoid confusion, in my previous post I used the term "message" and "item" to mean the same thing - sorry about that. Thought "items" would be clearer, but in my actual app the model is a "message" so I slipped. :)
on 2006-03-08 05:11
Update: I'm leaning toward a model that adds a TagList object that just has a user_id and a Tagging... so another table, but without the column duplication. Right now I'm thinking I may still be able to use acts_as_taggable with this model, but I'm still fleshing it out.