Hi all, My question is somewhat complicated, but bear with me. My project has a number of models: User, Program, and Team. Users belong to multiple Programs. Programs have multiple teams, but Teams belong to one program. For each Program a User belongs to, he can belong to multiple Teams. (Think of this in an athletic context where users are athletes, programs are universities). So my models look something like this: class User < ActiveRecord::Base has_many :user_programs has_many :programs, :through => :user_programs has_many :user_teams, :finder_sql => ''SELECT ut.* FROM user_teams AS ut JOIN user_programs AS up ON up.user_program_id = ut.user_program_id JOIN users AS u ON up.user_id = u.user_id WHERE u.user_id = #{id}'' has_many :teams, :finder_sql => ''SELECT t.* FROM teams AS t JOIN user_teams AS ut ON ut.team_id = t.team_id JOIN user_programs AS up ON up.user_program_id = ut.user_program_id JOIN users AS u ON up.user_id = u.user_id WHERE u.user_id = #{id}'' end class UserProgram < ActiveRecord::Base belongs_to :user belongs_to :program has_many :user_teams has_many :teams, :through => :user_teams end class Program < ActiveRecord::Base has_many :teams has_many :user_programs has_many :users, :through => :user_programs end class UserTeam < ActiveRecord::Base belongs_to :user_program belongs_to :team end class Team < ActiveRecord::Base belongs_to :program has_many :user_teams has_many :users, :finder_sql => ''SELECT u.* FROM users AS u JOIN user_programs AS up ON u.user_id = up.user_id JOIN user_teams AS ut ON up.user_program_id = ut.user_program_id JOIN teams as t ON ut.team_id = t.team_id WHERE t.team_id = #{id}'' has_many :user_programs, :through => :user_teams end Now what I would like to do is be able to edit the users on a team from the Edit Team view using checkboxes, that is, include something like this in my edit form: <% for user in @program_users %> <div> <%= check_box_tag "team[user_ids][]", user.id, @team.users.include?(user) %> <%= user.name %> </div> <% end %> And then in my TeamsController, do the standard : def update # in case all users are deselected, create empty array as it won''t exist params[:team][:user_ids] ||= [] @team = Team.find(params[:id]) if @team.update_attributes(params[:team]) ....... end When I try this however, Rails (not unsurprisingly) produces some pretty strange SQL: When removing users 1237 and 1238 from team 1: Mysql::Error: Unknown column ''team_id'' in ''where clause'': UPDATE `users` SET team_id = NULL WHERE (team_id = 1 AND user_id IN (1237,1238)) When adding user 1242 to team 1: UPDATE `users` SET `perishable_token` = ''z7imelr6kqnwiD1dQtTt'' WHERE `user_id` = 1242 (which is even more crazy... maybe something else is going on there...) Clearly that approach is not going to work without some changes..... Note that everything worked fine when I didn''t include any mention of program in UserTeam, and it was just a simple has_many :through join table for users and teams (I want to change the relationship so that when a user leaves a program and the UserProgram record is deleted, the MySQL foreign key constraints will cause the UserTeam records to be deleted as well). What''s the best way of editing these team members? Let me know if I''m completely off-base here. Thanks! -David -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.