Hello shafiqkr：）

I don't know which kind of technology you are now using……So if you are using the general ADO.NET，I think you can refer this nice article of Avoiding Concurrency at：

http://www.asp.net/web-forms/tutorials/data-access/editing,-inserting,-and-deleting-data/implementing-optimistic-concurrency-cs

For EF，You should set properties and make your EF data model can avoid Multiple users Concurrency problem at：

http://blogs.msdn.com/b/cesardelatorre/archive/2008/09/05/optimistic-concurrency-updates-using-entity-framework-in-n-tier-and-n-layer-applications-part-2.aspx