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 <[email protected]> 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
