What is a Transaction in Oracle?

Question

Below is the one of the interview question which was held by Oracle

If a transaction is very large, and the rollback segment is not able to hold the rollback information, then will the transaction span across different rollback segments or will it terminate?

Answer 1

A transaction is a Logical unit of work that compromises one or more SQL Statements executed by a single User. According to ANSI, a transaction begins with first executable statement and ends when it is explicitly committed or rolled back.

Answer 2

A transaction is a unit of work that is performed against a database. Transactions are units or sequences of work accomplished in a logical order, whether in a manual fashion by a user or automatically by some sort of a database program.

There are following commands used to control transactions:

COMMIT: to save the changes.

ROLLBACK: to rollback the changes.

SAVEPOINT: creates points within groups of transactions in which to ROLLBACK

SET TRANSACTION: Places a name on a transaction.

Transactional control commands are only used with the DML commands INSERT, UPDATE and DELETE only. They can not be used while creating tables or dropping them because these operations are automatically commited in the database.