Thanks, Martin! I've headed down path #2, but I thought of posting here just in case there already existed a custom validation. Maybe this isn't a very common thing. Seems to be that usually it's explicit in the direction (i.e. "husband => wife" relationship or "employer" => "employee" or something like that).
-Danimal On Mar 10, 7:26 pm, Martin Streicher <martin.streic...@gmail.com> wrote: > Two ideas: > > 1. Create two unique database indices, one each for each pairing order > and catch the exception on save on create. > > 2. Do it manually. > > errors.add(:base, 'already exists') if > (Klass.where(:sender_id => sender.id, :receiver_id => receiver.id) + > Klass.where(:sender_id => receiver.id, :receiver_id => > sender.id)).any? > > On Mar 10, 2:09 pm, Danimal <fightonfightw...@gmail.com> wrote: > > > Hello! > > > I'm trying to figure out how to make two columns unique regardless of > > order. If order mattered, I could scope the validates_uniqueness_of, > > like > > this:http://stackoverflow.com/questions/1633297/how-do-i-validate-two-fiel... > > > But that's only one way. What if I have two columns, called "sender" > > and "receiver" and it doesn't really matter who is the sender and who > > is the receiver as long as that "grouping" doesn't exist previously. > > > For example, assume I have this already in the database: > > Sender = 1, Receiver = 2 > > > Then, the following should occur: > > Sender = 1, Receiver = 3 # => PASS > > Sender = 1, Receiver = 2 # => FAIL > > Sender = 2, Receiver = 1 # => FAIL > > Sender = 3, Receiver = 1 # => FAIL (if the first one that passed > > already happened) > > > I tried this: > > > validates_uniqueness_of :sender_id, :scope => :receiver_id > > validates_uniqueness_of :receiver_id, :scope => :sender_id > > > But that doesn't quite do it because they aren't tied together. I can > > custom-validate this but I was wondering if this pattern has already > > been accounted for somehow. > > > Any pointers/references? > > > Thanks! > > > -Danimal -- 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 this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
