writing the perfect internet dating profile - Selecting from and updating the same table oracle


Furthermore, readers of data will never have to wait for writers of the same data rows.

Row Locks (TX) Row-level locks serve a primary function to prevent multiple transactions from modifying the same row.

Whenever a transaction needs to modify a row, a row lock is acquired by Oracle.

Transactions will acquire exclusive row locks for individual rows that are using modified INSERT, UPDATE, and DELETE statements and also for the SELECT with the FOR UPDATE clause.

Modified rows are always locked in exclusive mode with Oracle so that other transactions do not modify the row until the transaction which holds the lock issues a commit or is rolled back.

(a deadlock) This constant row-level locking means that you do not have to do frequent commits to release Oracle locks.