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.
