Would like to know the best practice being followed on handling the concurrency issues in the web application. The use case we have is similar to this. One last room is available in a hotel and 2 or more users try to reserve that same room at the same time. Only one user gets it and the other one or more get a message that the room has just been occupied. The application will be using Oracle or MS-SQLServer database. Would like to know the best place and way to check. Is it purely at database or at dao or business object? How can this be done? Any pointer to good articles will help. Thanks Jayaraman