search for: has_many_and_belongs_to_many

Hi there, Just a simple question I guess, but I am unable to find an anwser... How to delete a hmabtm relation? Any help will be appreciated :) Thanks, Fabrice. -- Posted via http://www.ruby-forum.com/.

...ry_id` int(10) unsigned default NULL, `risk_id` int(10) unsigned default NULL, `created_on` datetime default NULL, `updated_on` datetime default NULL, PRIMARY KEY (`id`) ) TYPE=InnoDB; the code in question is almost directly ripped from this tutorial: http://jrhicks.net/Projects/rails/has_many_and_belongs_to_many.pdf def update ... if @params[:risk_id] @industry.risks = Risk.find(@params[:risk_id]) if @params [:risk_id] else @industry.risks.clear end ... end and the error looks like this- NOTICE the `id` field getting set to 3... Mysql::Error: Duplicate entry ''3'...

...3 | 2 | East | | 4 | 3 | Yankees | | 5 | 3 | Red Sox | +----+-----------+---------+ parent_id is a FK to another domain id. A NULL parent_id indicates it is a top-level domain. So there would be a users and a domain_users table, and Domain model object would have a has_many_and_belongs_to_many relationship with users. But the problem is that would only allow me to query what users are directly in a given domain. In order to determine what users are in a given domain, you have to include the child domains has well. So what users are in domain MLB? The query would be: SELECT * from do...

...for some page which spills out the relations or associations within Rails, like: 1:1 relation: has_one, belongs_to in such and such way 1:many relation has_many, belongs_to in such and such way many:many relation: already has a tutorial of it''s own! (http:// jrhicks.net/Projects/rails/has_many_and_belongs_to_many.pdf) Thanks, Tom

I have a project, it has members. I have the data modeled, the ActiveRecord setup but I''m running into a block as how to accomplish this in a view. I would like if when the Project is being edited to present a list of all users, and then have a checkbox beside each name. Those selected would be a member, those who are not, obviously would not be. I am, however, not closed to

Hello all, I''ve been working with Ruby on Rails for a few weeks now. It''s difficult for me because I don''t have much experience with Ruby, Rails, MySQL, or any other web-languages. But I''m trudging on and learning a lot. I''ve been working on a web application for my dad''s website; it''s a simple content manager for

Hi everyone, I''m currently finishing the planning phase of a small project I want to create. I read a bunch of tutorials about ActiveRecord and the different way to link your "tables" with belongs_to, has_many, has_and_belong_..., etc... However I''m stillnot sure if what I''m trying to do will work *well* with ActiveRecord. So enough talk,

...ideas? I''ve seen the following article but it doesn''t go into enough detail and straight away bypasses the abstract migration tool using instead database specific sql (which suggests that the built in features may not exist for this yet): http://jrhicks.net/Projects/rails/ has_many_and_belongs_to_many.pdf On a similar note: How does rails handle the plural expansion of words like ''category''. i.e., if you have a migration called categories is it going to correctly use the singular for the model? That kind of naming scheme doesn''t seem to make sense in enough situ...

I''m working on a simple CMS. The main data type are "listings" a listing habtm (has_and_belongs_to_many) categories and subcategories. Subcategories belong_to categories. Subcategories are basically the same as categories, but they are treated differently in a few situations. The problem is, I can''t seem to write the view/controller/model code that allows me to