oracle--Control Transactions

One, roll back to the retention point

• Use the savepoint statement to create a savepoint in the current transaction.
• Use the ROLLBACK to savepoint statement to roll back to the saved point that was created.

Second, the data state before committing or rolling back

• The state of the data before the change can be restored.
• Other users cannot see changes made by the current user until the current user ends the transaction.
• The rows involved in the DML statement are locked and cannot be manipulated by other users.

Third, the status of the data after submission

• Changes to the data have been saved in the database.
• The data before the change has been lost.
• All users can see the results.
• The lock is released and other users can manipulate the data involved.
• All save points are freed.

Iv. Examples of transactions

1. Scott user updates the Employees table without committing (commit)
2. Then the system user wants to query for updates to get the Employees table

Select *  from for update; --but the database is not responding at this time

• You must wait until the Scott user commits the Employees table, and this SQL statement executes.

oracle--Control Transactions