Data Consistency and Concurrency Controlling in Air Ticket Selling in Different Sites by Using Notification- Reread Method (NRM)

Abstract

In the database management systems, concurrency control is an important problem for the simultaneous execution of transaction over a shared database can create several data integrity and consistency problem. In order to operate transactions concurrently on a shared database, a concurrency control algorithm must be adopted to coordinate their activities. The concurrency control of a distributed system is to ensure that the consistency of the database. Nowadays, travelling industry become stronger, enforcing travelling companies to run new branches in different locations.If users access a database concurrency, they may interfere with each other by attempting to read or write the same data items. Therefore, it is important to handle the order of each branch. When a user updates some data that have been accessed by other users in database, or execute an undo/redo operation, data consistency will probably be destroyed. In this system, a “Notification-Reread Method (NRM)” is introduced to solve the problem caused by concurrent processing.