ROLLBACK TRANSACTION (Transact-SQL)

Článek
05/12/2014

Rolls back an explicit or implicit transaction to the beginning of the transaction, or to a savepoint inside the transaction. You can use ROLLBACK TRANSACTION to erase all data modifications made from the start of the transaction or to a savepoint. It also frees resources held by the transaction.

Topic link icon Transact-SQL Syntax Conventions

Syntax

ROLLBACK { TRAN | TRANSACTION } 
     [ transaction_name | @tran_name_variable
     | savepoint_name | @savepoint_variable ] 
[ ; ]

Arguments

transaction_name
Is the name assigned to the transaction on BEGIN TRANSACTION. transaction_name must conform to the rules for identifiers, but only the first 32 characters of the transaction name are used. When nesting transactions, transaction_name must be the name from the outermost BEGIN TRANSACTION statement. transaction_name is always case sensitive, even when the instance of SQL Server is not case sensitive.
@ tran_name_variable
Is the name of a user-defined variable containing a valid transaction name. The variable must be declared with a char, varchar, nchar, or nvarchar data type.
savepoint_name
Is savepoint_name from a SAVE TRANSACTION statement. savepoint_name must conform to the rules for identifiers. Use savepoint_name when a conditional rollback should affect only part of the transaction.
@ savepoint_variable
Is name of a user-defined variable containing a valid savepoint name. The variable must be declared with a char, varchar, nchar, or nvarchar data type.

Error Handling

A ROLLBACK TRANSACTION statement does not produce any messages to the user. If warnings are needed in stored procedures or triggers, use the RAISERROR or PRINT statements. RAISERROR is the preferred statement for indicating errors.

General Remarks

ROLLBACK TRANSACTION without a savepoint_name or transaction_name rolls back to the beginning of the transaction. When nesting transactions, this same statement rolls back all inner transactions to the outermost BEGIN TRANSACTION statement. In both cases, ROLLBACK TRANSACTION decrements the @@TRANCOUNT system function to 0. ROLLBACK TRANSACTION savepoint_name does not decrement @@TRANCOUNT.

ROLLBACK TRANSACTION cannot reference a savepoint_name in distributed transactions started either explicitly with BEGIN DISTRIBUTED TRANSACTION or escalated from a local transaction.

A transaction cannot be rolled back after a COMMIT TRANSACTION statement is executed, except when the COMMIT TRANSACTION is associated with a nested transaction that is contained within the transaction being rolled back. In this instance, the nested transaction will also be rolled back, even if you have issued a COMMIT TRANSACTION for it.

Within a transaction, duplicate savepoint names are allowed, but a ROLLBACK TRANSACTION using the duplicate savepoint name rolls back only to the most recent SAVE TRANSACTION using that savepoint name.

Interoperability

In stored procedures, ROLLBACK TRANSACTION statements without a savepoint_name or transaction_name roll back all statements to the outermost BEGIN TRANSACTION. A ROLLBACK TRANSACTION statement in a stored procedure that causes @@TRANCOUNT to have a different value when the stored procedure completes than the @@TRANCOUNT value when the stored procedure was called produces an informational message. This message does not affect subsequent processing.

If a ROLLBACK TRANSACTION is issued in a trigger:

All data modifications made to that point in the current transaction are rolled back, including any made by the trigger.
The trigger continues executing any remaining statements after the ROLLBACK statement. If any of these statements modify data, the modifications are not rolled back. No nested triggers are fired by the execution of these remaining statements.
The statements in the batch after the statement that fired the trigger are not executed.

@@TRANCOUNT is incremented by one when entering a trigger, even when in autocommit mode. (The system treats a trigger as an implied nested transaction.)

ROLLBACK TRANSACTION statements in stored procedures do not affect subsequent statements in the batch that called the procedure; subsequent statements in the batch are executed. ROLLBACK TRANSACTION statements in triggers terminate the batch containing the statement that fired the trigger; subsequent statements in the batch are not executed.

The effect of a ROLLBACK on cursors is defined by these three rules:

With CURSOR_CLOSE_ON_COMMIT set ON, ROLLBACK closes, but does not deallocate all open cursors.
With CURSOR_CLOSE_ON_COMMIT set OFF, ROLLBACK does not affect any open synchronous STATIC or INSENSITIVE cursors or asynchronous STATIC cursors that have been fully populated. Open cursors of any other type are closed but not deallocated.
An error that terminates a batch and generates an internal rollback deallocates all cursors that were declared in the batch containing the error statement. All cursors are deallocated regardless of their type or the setting of CURSOR_CLOSE_ON_COMMIT. This includes cursors declared in stored procedures called by the error batch. Cursors declared in a batch before the error batch are subject to rules 1 and 2. A deadlock error is an example of this type of error. A ROLLBACK statement issued in a trigger also automatically generates this type of error.

Locking Behavior

A ROLLBACK TRANSACTION statement specifying a savepoint_name releases any locks that are acquired beyond the savepoint, with the exception of escalations and conversions. These locks are not released, and they are not converted back to their previous lock mode.

Permissions

Requires membership in the public role.

Examples

The following example shows the effect of rolling back a named transaction.

USE tempdb;
GO
CREATE TABLE ValueTable ([value] int;)
GO

DECLARE @TransactionName varchar(20) = 'Transaction1';

--The following statements start a named transaction,
--insert two rows, and then roll back
--the transaction named in the variable @TransactionName.
--Another statement outside of the named transaction inserts two rows.
--The query returns the results of the previous statements.

BEGIN TRAN @TransactionName
       INSERT INTO ValueTable VALUES(1), (2);
ROLLBACK TRAN @TransactionName;

INSERT INTO ValueTable VALUES(3),(4);

SELECT [value] FROM ValueTable;

DROP TABLE ValueTable;

--Results
--value
-------------
--3
--4

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