# Rails 1.1: Is HABTM obsolete? **URL:** \ **Category:** Rails\ **Created:** [March 29, 2006, 12:01am UTC](https://www.ruby-forum.com/t/rails-1-1-is-habtm-obsolete/89579 "2006-03-29T00:01:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![joe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b9e5f3/32.png) [@joe](https://www.ruby-forum.com/u/joe)\ **Post date:** [March 29, 2006, 12:01am UTC](https://www.ruby-forum.com/t/rails-1-1-is-habtm-obsolete/89579/1 "2006-03-29T00:01:41Z")
Does the new has\_many :through and belongs\_to :through obsolete (well, replace and essentially deprecate) has\_and\_belongs\_to\_many? Joe ---
**Author:** ![joe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b9e5f3/32.png) [@joe](https://www.ruby-forum.com/u/joe)\ **Post date:** [March 29, 2006, 12:39am UTC](https://www.ruby-forum.com/t/rails-1-1-is-habtm-obsolete/89579/2 "2006-03-29T00:39:15Z")
Not necessarily. We don’t always have a rich association. It might be enough to know that A has many of B, without needing another model C to describe the association. Or put another way, if we didn’t have habtm, we couldn’t associate A to B without creating a C, even if C is meaningless. ---
**Author:** ![joe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b9e5f3/32.png) [@joe](https://www.ruby-forum.com/u/joe)\ **Post date:** [March 29, 2006, 1:23am UTC](https://www.ruby-forum.com/t/rails-1-1-is-habtm-obsolete/89579/3 "2006-03-29T01:23:08Z")
On 3/28/06, Kenneth L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Not necessarily. We don’t always have a rich association. It might > be enough to know that A has many of B, without needing another model > C to describe the association. I’m trying to get this clear in my mind as well. Are you saying that if the bridge table C has additional fields that are unique to the association, then that would be a candidate for the has\_many :through and belongs\_to :through construct? Otherwise, use the habtm construct? Or put another way, if we didn’t have > > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). > > > > * * * > > > > Rails mailing list > > removed\_email\_address@domain.invalid > > [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails) > > * * * > > Rails mailing list > removed\_email\_address@domain.invalid > [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails) – Best Regards, -Larry “Work, work, work…there is no satisfactory alternative.” — E.Taft Benson ---
**Author:** ![joe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b9e5f3/32.png) [@joe](https://www.ruby-forum.com/u/joe)\ **Post date:** [March 29, 2006, 2:05am UTC](https://www.ruby-forum.com/t/rails-1-1-is-habtm-obsolete/89579/4 "2006-03-29T02:05:15Z")
Larry K. wrote: > Are you saying that if the bridge table C has additional fields that are > unique to the association, then that would be a candidate for the has\_many > :through and belongs\_to :through construct? Otherwise, use the habtm > construct? That’s a good start on it. has\_many :through lets you have rich associations (read and write atrributes in the join model), and it also lets you eagerly load data using :includes. If all you have is a simple join table, then habtm might be fine for you. Also, habtm is still necessary for dealing with legacy database schemas that don’t have a primary key on the join table. I’ve been writing about has\_many :through associations on my aptly named blog. You might find some stuff there worth reading if you’re interested in them. – Josh S. [http://blog.hasmanythrough.com](http://blog.hasmanythrough.com)