Hi all, I am building web application by using Oracle data base. Because different uders will manipulate the same data record at the same time. Could someone please help me for the following questions: 1. How can I handel the concurrently DML (insert, update, delete) opertions on same data record by different users? Can I use synchronied method in update, insert, and delete opertionns? Or other better method ?? 2. When user 1 select data from table , user 2 update or delete the date in the same table concurrently. Do I need to set transaction isolation level to TRANSACTION_READ_COMMITED or refreshRow() to get the updated data? thanks all.