# Relationship Question (STI) **URL:** \ **Category:** Rails\ **Created:** [February 6, 2006, 11:54pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801 "2006-02-06T23:54:33Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Dylan\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/34f0e0/32.png) [@Dylan\_S](https://www.ruby-forum.com/u/Dylan_S)\ **Post date:** [February 6, 2006, 11:54pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801/1 "2006-02-06T23:54:33Z")
My girlfriend and I have been dating for two years, and she just told me she has an STI… Actually, I currently have three different models, like: Dog, Whale, Monkey They all have some similar attributes, but, they are unique enough to break into their own models. I could use STI, but I think the table would just have too many columns. Now, I wanted to let the Dog’s, Whale’s and Monkey’s be buddies, and keep track of their relationships. I created a Buddies table (with monkey\_id, dog\_id, whale\_id), and had has\_many relationships to link them all up. This will work… however, if I wanted to list all of a Monkey’s Buddies… it get’s tricky. I have to query the Buddies table to get the relationships, then query both the Whale and Monkey to get the appropriate objects back. I saw Chad’s HABTM example using STI in the Recipes book… but I’m trying to stay away from STI. # Any thoughts ? Also, sorry for the bizzare post… I have the flu ! Dylan ---
**Author:** ![Dylan\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/34f0e0/32.png) [@Dylan\_S](https://www.ruby-forum.com/u/Dylan_S)\ **Post date:** [February 7, 2006, 6:28pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801/2 "2006-02-07T18:28:51Z")
On 2/6/06, Dylan S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > # Any thoughts ? Also, sorry for the bizzare post… I have the flu ! > > Dylan Dylan, if you don’t get an answer before then (soon!), I have a recipe or two already written for the next release of the book that I think will answer this for you. To do it cleanly, you’re probably going to want to be on Edge Rails. – Chad F. [http://chadfowler.com](http://chadfowler.com) [http://pragmaticprogrammer.com/titles/fr\_rr/](http://pragmaticprogrammer.com/titles/fr_rr/) (Rails Recipes - In Beta!) [http://pragmaticprogrammer.com/titles/mjwti/](http://pragmaticprogrammer.com/titles/mjwti/) (My Job Went to India, and All I Got Was This Lousy Book) [http://rubycentral.org](http://rubycentral.org) [http://rubygarden.org](http://rubygarden.org) [http://rubygems.rubyforge.org](http://rubygems.rubyforge.org) (over one million gems served!) ---
**Author:** ![Dylan\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/34f0e0/32.png) [@Dylan\_S](https://www.ruby-forum.com/u/Dylan_S)\ **Post date:** [February 7, 2006, 6:57pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801/3 "2006-02-07T18:57:04Z")
Ahh… thank you Chad ! I’ve been skimming the AR docs trying to conjure up a way to make this work, but to no avail thus far. In regard to the edge solution, I actually found a post by Tobias Lutke in which he described a few new features that could solve this… however, I can’t find the thread for the life of me. I’ll keep plugging away at this (will get on edge a/s/a/p), but it would be great if you could share those recipes !.. or at least hint as to what features in edge to use 🙂 BTW… I’m a proud owner of the PDF at the moment, and can’t wait for the end result. It’s great so far. # Thanks ! Dylan ---
**Author:** ![Dylan\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/34f0e0/32.png) [@Dylan\_S](https://www.ruby-forum.com/u/Dylan_S)\ **Post date:** [February 7, 2006, 11:44pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801/4 "2006-02-07T23:44:16Z")
Now, if I _could_ possibly squeeze my models into a STI setup, would it be better (performance wise) to use this instead of the :polymorphic approach ? I’d assume so, as there is only one join table, and one self-referencing table… as opposed to the polymorphic approach, which looks like it could deal with a few more tables ? ---
**Author:** ![Dylan\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/34f0e0/32.png) [@Dylan\_S](https://www.ruby-forum.com/u/Dylan_S)\ **Post date:** [February 7, 2006, 7:09pm UTC](https://www.ruby-forum.com/t/relationship-question-sti/101801/5 "2006-02-07T19:09:49Z")
On 2/7/06, Dylan S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Ahh… thank you Chad ! > > I’ve been skimming the AR docs trying to conjure up a way to make this work, > but to no avail thus far. > In regard to the edge solution, I actually found a post by Tobias Lutke in > which he described a few new features that could solve this… however, I > can’t find the thread for the life of me. > > I’ll keep plugging away at this (will get on edge a/s/a/p), I’m also covering this in the next release of the book if it gives anyone any trouble with the current docs. > but it would be > great if you could share those recipes !.. or at least hint as to what > features in edge to use 🙂 Look at polymorphic associations and join models. The source code for DHH’s acts\_as\_taggable plugin might give you some hints. > BTW… I’m a proud owner of the PDF at the moment, and can’t wait for the > end result. It’s great so far. Thanks! – Chad F. [http://chadfowler.com](http://chadfowler.com) [http://pragmaticprogrammer.com/titles/fr\_rr/](http://pragmaticprogrammer.com/titles/fr_rr/) (Rails Recipes - In Beta!) [http://pragmaticprogrammer.com/titles/mjwti/](http://pragmaticprogrammer.com/titles/mjwti/) (My Job Went to India, and All I Got Was This Lousy Book) [http://rubycentral.org](http://rubycentral.org) [http://rubygarden.org](http://rubygarden.org) [http://rubygems.rubyforge.org](http://rubygems.rubyforge.org) (over one million gems served!)