What is the oracle rollback command?

Oracle Rollback Command

The Oracle rollback command is used to undo changes made in an uncommitted transaction.

Command syntax

ROLLBACK;

Function

##ROLLBACK The command will save the current uncommitted transaction. All changes are rolled back to the previous commit point. It undoes all uncommitted insert, update, and delete operations.

Usage scenarios

When an error occurs or the user wants to undo all changes made within a period of time.
• In long-running transactions,
• ROLLBACK can be used to roll back intermediate changes that may not be needed.

When to use

ROLLBACK The command is typically used in the following situations:

Transaction processing An error was encountered.
• The user entered incorrectly or accidentally updated data.
• Want to undo all changes made since the last commit.

Note

• ROLLBACK command cannot undo changes in a committed transaction.
If other operations are performed before executing
• ROLLBACK, these operations cannot be rolled back.
• ROLLBACK Will roll back all uncommitted transactions, including nested transactions.

Example

The following example demonstrates how to use the

ROLLBACK command:

BEGIN TRANSACTION;

-- 更新员工表
UPDATE employees SET salary = salary * 1.10 WHERE department_id = 20;

-- 假设发生错误
RAISE_APPLICATION_ERROR(-20001, '数据更新失败');

ROLLBACK; -- 回滚所有未提交的更改

SELECT * FROM employees WHERE department_id = 20; -- 查看更新已回滚

In the example, the update operation Rolling back due to errors, the data in the employees table remains unchanged.

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