On May 31, 2006, at 12:28, Daniel wrote: > Hi, > > I have three Models > > User, Group and File. > > User habtm group > Group habtm File > > How can I find all that files that a particular user has access to? > eg user.groups.files ? The Rails-specific list (http://lists.rubyonrails.org/mailman/ listinfo/rails) and wiki and things may give you a better answer (particularly in terms of things like query optimisation) than you'll get here, but... user.groups is an array, it's not the array which has a file attribute, but each individual group in it, so maybe something like this: class User def files self.groups.inject([]) { |arr, group| arr + group.files } end end matt smillie.