CODEWITHSUNDEEP
sqlsql-serversql-server-2005transactions
jonathanpeppers
jonathanpeppers

Reputation: 26505

SQL Server - transactions roll back on error?

We have client app that is running some SQL on a SQL Server 2005 such as the following:

BEGIN TRAN;
INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
COMMIT TRAN;

It is sent by one long string command.

If one of the inserts fail, or any part of the command fails, does SQL Server roll back the transaction? If it does not rollback, do I have to send a second command to roll it back?

I can give specifics about the api and language I'm using, but I would think SQL Server should respond the same for any language.

Upvotes: 249

Views: 298254

Answers (6)

TheMet4lGod
TheMet4lGod

Reputation: 116

Throwing this out as an alternative method, you can also capture the error number after each statement and then use an if statement to determine if to commit or rollback. The accepted answer is the best one-liner, but if you want to know more about what issue you're getting rather than just rolling it back you can use the example below and add some additional information for seeing the issue. Of course, you could also do a Try-Catch block with RAISERROR.

Here's an example of what I have as just something quick:

DECLARE @errorNumber int;
DECLARE @error1 int;
DECLARE @error2 int;

BEGIN TRANSACTION;
    INSERT INTO [table2] ([field1], [field2])
    SELECT [fieldA], [fieldB]
    FROM [table1];
        
    SET @error1 = @@ERROR;
    SET @errorNumber = @error1;

    UPDATE [table3]
    SET [field1] =
        (SELECT COUNT(ID)
        FROM [table2]
        WHERE [table2].[fieldA] = [table3].[field2])
    WHERE [field1] IS NULL;
        
    SET @error2 = @@ERROR;
    SET @errorNumber += @error2;

IF @errorNumber = 0
    COMMIT TRANSACTION;
ELSE
    BEGIN
        ROLLBACK TRANSACTION;
        IF @error1 > 0
            PRINT CONCAT('Transaction rolled back with error number: ',@error1);
        IF @error2 > 0
            PRINT CONCAT('Transaction rolled back with error number: ',@error2);
    END

Upvotes: 1

Raj More
Raj More

Reputation: 48034

You are correct in that the entire transaction will be rolled back. You should issue the command to roll it back.

You can wrap this in a TRY CATCH block as follows

BEGIN TRY
    BEGIN TRANSACTION

        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);
        INSERT INTO myTable (myColumns ...) VALUES (myValues ...);

    COMMIT TRAN -- Transaction Success!
END TRY
BEGIN CATCH
    IF @@TRANCOUNT > 0
        ROLLBACK TRAN --RollBack in case of Error

    -- <EDIT>: From SQL2008 on, you must raise error messages as follows:
    DECLARE @ErrorMessage NVARCHAR(4000);  
    DECLARE @ErrorSeverity INT;  
    DECLARE @ErrorState INT;  

    SELECT   
       @ErrorMessage = ERROR_MESSAGE(),  
       @ErrorSeverity = ERROR_SEVERITY(),  
       @ErrorState = ERROR_STATE();  

    RAISERROR (@ErrorMessage, @ErrorSeverity, @ErrorState);  
    -- </EDIT>
END CATCH

Upvotes: 252

samwise
samwise

Reputation: 2267

Here the code with getting the error message working with MSSQL Server 2016:

BEGIN TRY
    BEGIN TRANSACTION 
        -- Do your stuff that might fail here
    COMMIT
END TRY
BEGIN CATCH
    IF @@TRANCOUNT > 0
        ROLLBACK TRAN

        DECLARE @ErrorMessage NVARCHAR(4000) = ERROR_MESSAGE()
        DECLARE @ErrorSeverity INT = ERROR_SEVERITY()
        DECLARE @ErrorState INT = ERROR_STATE()

    -- Use RAISERROR inside the CATCH block to return error  
    -- information about the original error that caused  
    -- execution to jump to the CATCH block.  
    RAISERROR (@ErrorMessage, @ErrorSeverity, @ErrorState);
END CATCH

Upvotes: 62

Vitaly
Vitaly

Reputation: 310

From MDSN article, Controlling Transactions (Database Engine).

If a run-time statement error (such as a constraint violation) occurs in a batch, the default behavior in the Database Engine is to roll back only the statement that generated the error. You can change this behavior using the SET XACT_ABORT statement. After SET XACT_ABORT ON is executed, any run-time statement error causes an automatic rollback of the current transaction. Compile errors, such as syntax errors, are not affected by SET XACT_ABORT. For more information, see SET XACT_ABORT (Transact-SQL).

In your case it will rollback the complete transaction when any of inserts fail.

Upvotes: 28

user121301
user121301

Reputation:

You can put set xact_abort on before your transaction to make sure sql rolls back automatically in case of error.

Upvotes: 265

Quassnoi
Quassnoi

Reputation: 425753

If one of the inserts fail, or any part of the command fails, does SQL server roll back the transaction?

No, it does not.

If it does not rollback, do I have to send a second command to roll it back?

Sure, you should issue ROLLBACK instead of COMMIT.

If you want to decide whether to commit or rollback the transaction, you should remove the COMMIT sentence out of the statement, check the results of the inserts and then issue either COMMIT or ROLLBACK depending on the results of the check.

Upvotes: 14

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