Marnen Laibow-Koser wrote: > Cathal O'Riordan wrote: > [...] >> My concern is that my code won't guard against a race condition where >> 2 or more users try to register for a course that is near it capacity >> limit. My first thought was to wrap the registration code in a >> transaction and rollback if the capacity of registrations on a course >> has been exceeded. > [...] > > Use check constraints in the DB and let *it*, not your app, worry about > concurrency issues!
That's one approach. Wrapping it up in a transaction with read isolation would work fine too. Alternatively (and better for concurrency), keep a counter cache on the registration_count and use the default isolation level. -- Roderick van Domburg -- 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 [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 -~----------~----~----~----~------~----~------~--~---
