# Simple Association Help **URL:** \ **Category:** Rails\ **Created:** [January 27, 2007, 12:58am UTC](https://www.ruby-forum.com/t/simple-association-help/83538 "2007-01-27T00:58:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![aliasxneo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/df705f/32.png) [@aliasxneo](https://www.ruby-forum.com/u/aliasxneo)\ **Post date:** [January 27, 2007, 12:58am UTC](https://www.ruby-forum.com/t/simple-association-help/83538/1 "2007-01-27T00:58:23Z")
I’m creating my first Ruby application (by myself not following a book) so things are a little rough for me in the beggining but I have gotten a hang of a lot of things. What I have is a basic article system where users can login and post articles and comment on other articles. I have the basic system for showing a simple list of articles and then showing an individual article along with any comments it has. Now I am trying to implement the user part. A user can write one or more articles and one or more comments. So, in my article model I placed: has\_one :user And then in my comment model I placed the same thing: has\_one :user Then in my user model I placed: has\_many :article has\_many :comment It seems like it should work fine except I am getting an error: Mysql::Error: Unknown column ‘users.article\_id’ in ‘where clause’: SELECT \* FROM users WHERE (users.article\_id = 1) LIMIT 1 I understand the error but it’s trying to do something I don’t want it to do. I want an article to have a user\_id since every article has one user. I don’t want the user to have an article\_id because a user has one or more articles. Somehow I got confused here and Ruby is trying to access a article\_id which doesn’t exist of course because that’s not how I planned it out. Can anyone explain to me what I did wrong and how I can fix this? Thanks. Cheers, - Josh ---
**Author:** ![aliasxneo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/df705f/32.png) [@aliasxneo](https://www.ruby-forum.com/u/aliasxneo)\ **Post date:** [January 27, 2007, 1:47am UTC](https://www.ruby-forum.com/t/simple-association-help/83538/2 "2007-01-27T01:47:35Z")
Oh to the glory of reading books 🙂 I think you want a one-to-many relationship, if so, this is what you need: Article model: belongs\_to :user Comment model: belongs\_to :user User model: has\_many :article has\_many :comment Straight frome _the_ book (Agile Web D. with Rails) “There’s an important rule illustrated here: the model for the table that contains the foreign key always has the belongs\_to declaration.” Therefor Article and Comments must have a column called user\_id Hope that helps -K On Jan 26, 3:58 pm, Josh G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![aliasxneo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/df705f/32.png) [@aliasxneo](https://www.ruby-forum.com/u/aliasxneo)\ **Post date:** [January 27, 2007, 2:07am UTC](https://www.ruby-forum.com/t/simple-association-help/83538/3 "2007-01-27T02:07:36Z")
I believe that would be… Article model: belongs\_to :user Comment model: belongs\_to :user User model: has\_many :articles has\_many :comments also, you must remember to create the foreign keys in your database. In this case they would go in the Comment and User tables in the database. (you need a user\_id column in these tables for the association to work) ---
**Author:** ![aliasxneo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/df705f/32.png) [@aliasxneo](https://www.ruby-forum.com/u/aliasxneo)\ **Post date:** [February 9, 2007, 12:46am UTC](https://www.ruby-forum.com/t/simple-association-help/83538/4 "2007-02-09T00:46:32Z")
Do it like this: belongs\_to :article belongs\_to :user They can not share a line. On Jan 26, 6:33 pm, Josh G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![aliasxneo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/df705f/32.png) [@aliasxneo](https://www.ruby-forum.com/u/aliasxneo)\ **Post date:** [January 27, 2007, 3:33am UTC](https://www.ruby-forum.com/t/simple-association-help/83538/5 "2007-01-27T03:33:19Z")
Kim wrote: > Oh to the glory of reading books 🙂 > I think you want a one-to-many relationship, if so, this is what you > need: > > Article model: > belongs\_to :user > > Comment model: > belongs\_to :user > > User model: > has\_many :article > has\_many :comment > > Straight frome _the_ book (Agile Web D. with Rails) > > “There’s an important rule illustrated here: the model for the table > that contains > the foreign key always has the belongs\_to declaration.” > > Therefor Article and Comments must have a column called user\_id > > Hope that helps -K > > On Jan 26, 3:58 pm, Josh G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Okay I seem to have a problem now. The article seemed to work fine, but a comment belongs to both an article and a user so I put: belongs\_to :article, :user And got: undefined method `include?’ for :user:Symbol What’s wrong with that?