Sa S. wrote in post #1074690: > Thanks for the help! Although I'm not sure I totally understand it, > still a bit of a noob. So if I wanted to do something as simple as > subtract the user's handicap from the course's handicap, how would I > create a method for that in the Player model? (sorry maybe you might > have done it already but I'm not sure what .gt and .lt mean) > > Basically something like > > class Player > > def handicaps_difference > Course.handicap - handicap (from the player) > end
Given that with a many-to-many relationship (has_and_belongs_to_many) a single player will be associated to many courses and one course will be associated to many players. So in order to do that sort of math you'll need to iterate through them. Player will have a method, added by ActiveRecord named "courses"... a_player.courses I assume here that you want to first select a player: a_player = Player.find(:id) Then I assume you want to list all the courses associated with this one player with the handicap difference: a_player.courses.each do |course| puts course.handicap_difference(a_player) end Where each course can calculate the handicap difference with a given player: class Course def handicap_different(player) player.handicap - self.handicap end end But even better would be to expose the join table with its own object using has_many :through. Then you can put the calculation in the object that "knows" about both sides: class CourseAssignment # The exposed join table has_one :player has_one :course def handicap_difference player.handicap - course.handicap end end Again the "player" and "course" methods will be added by ActiveRecord to the CourseAssignment object. http://guides.rubyonrails.org/association_basics.html#choosing-between-has_many-through-and-has_and_belongs_to_many -- Posted via http://www.ruby-forum.com/. -- 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@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.