Transaction Control Language (TCL) in Oracle SQL - Day 31
In Oracle SQL, TCL (Transaction Control Language) refers to a set of commands that are used to manage transactions within the database. Transactions are units of work that consist of one or more SQL statements and are executed as a single logical operation. TCL commands allow you to control the behavior and outcome of transactions.
Here are the key TCL commands in Oracle SQL:
1. COMMIT: The COMMIT command is used to permanently save the changes made within a transaction to the database. It marks the successful completion of the transaction and makes the changes visible to other users. Once a COMMIT is executed, the changes cannot be rolled back.
2. ROLLBACK: The ROLLBACK command is used to undo or cancel the changes made within a transaction. It restores the database to its state before the transaction started. ROLLBACK can be used to handle errors or exceptions during the transaction, ensuring that any erroneous changes are not persisted.
3. SAVEPOINT: SAVEPOINT command is used to set a named marker within a transaction, allowing you to create a point to which you can rollback. SAVEPOINTs provide a way to create intermediate checkpoints within a transaction, enabling partial rollbacks while preserving the changes made up to a specific point.
4. SET TRANSACTION: The SET TRANSACTION command is used to set transaction characteristics such as isolation level and transaction name. It allows you to control how concurrent transactions interact and how changes are visible to other users.
TCL commands play a crucial role in ensuring data consistency, integrity, and reliability within the database. They provide control over the logical units of work and allow you to manage the outcome of transactions. By using COMMIT, ROLLBACK, SAVEPOINT, and SET TRANSACTION commands effectively, you can control and maintain the integrity of your database transactions.