I'm a fan of using GOTO to make error handling easier:

DECLARE @err int

UPDATE cart SET .....

SET @err = @@ERROR
IF @err != 0 GOTO __cleanup

UPDATE nextTable SET ...

SET @err = @@ERROR
IF @err != 0 GOTO __cleanup

__cleanup:
IF @err != 0
BEGIN
 -- cleanup code goes here
END

or something like that

-Mike



>>>Why your suggestion is better? If UserID exists, we would need to modify, so we don't have to search?
>>
>>Remember that INSERT, UPDATE, and DELETEs are two step commands. In the first step, SQL Server must find the applicable row or in the case of INSERT, it must find the location to put the new row. In performing this step, SQL Server uses a special lock - UPDATE. It is different than a SHARED lock. It affects concurrency more than a SHARED lock but less than EXCLUSIVE.
>>
>>> UPDATE cart
>>> SET LastModTs = CURRENT_TIMESTAMP,
>>> @CartID = CartID
>>> FROM cart
>>> WHERE UserID = @tcUserID
>>>
>>>Incorrect syntax near UserID
>>
>>You don't need to use this form of UPDATE. Try this
>>
>>UPDATE cart
>> SET @cartID = cartID
>> ,lastModified = CURRENT_TIMESTAMP
>>WHERE
>> userid = @tnUserID
>>
>>Now, if lastModified is defined with the TIMESTAMP datatype, you don't have to explicitly update it. SQL Server will automatically do it.
>>
>>>Also am I getting right, that you don't have to close IF statements, e.g. is this valid:
>>>Does END means an early exit point from the procedure?
>>
>>BEGIN and END are use to group statements into blocks. TSQL is similar to C, C++, and C# in that conditional and looping statements only affect the statement that appear directly after it. Executing the following:
>>
>>IF (1=0)
>> PRINT 'Hello'
>> PRINT 'World'
>>
>>Will produce "World" since the first PRINT is skipped. But, wrapping BEGIN and END around the two prints will produce the output as you might expect:
>>
>>IF (1=0)
>> BEGIN
>> PRINT 'Hello'
>> PRINT 'World'
>> END
>>
>>Nothing will be displayed when the above snippet of code is executed.
>>
>>-Mike
>
>Now I understand. That's great, that and how easily you explained it to me.
>
>Thanks a lot.
>So, it would be:

>-- Code from Mike Levy
>IF EXISTS (SELECT CartID FROM cart WHERE UserID = @tcUserID)
>   BEGIN
>   	UPDATE cart
>   	SET @CartID = CartID,
>   	LastModTs = CURRENT_TIMESTAMP
>   	WHERE UserID = @tcUserID
>   	IF @@ERROR <> 0
>          BEGIN
>            ROLLBACK TRAN
>            PRINT 'ERROR: An error occurred while attempting to update record to the Cart Table.'
>            RETURN 4
>        END
>   END
>ELSE
>-- New User
>    BEGIN
>	 INSERT INTO cart (UserID) values (@tcUserID)
>
>	 SELECT @CartID = SCOPE_IDENTITY()
>         IF @@ERROR <> 0
>          BEGIN
>            ROLLBACK TRAN
>            PRINT 'ERROR: An error occurred while attempting to insert record to the Cart Table.'
>            RETURN 5
>          END
>     END

?
>
>How can I highlight a block of code and ident it correctly?
>
>Or should I use one place to handle errors, e.g. like:
>

>USE pubs
>GO
>DECLARE @del_error int, @ins_error int
>-- Start a transaction.
>BEGIN TRAN
>
>-- Execute the DELETE statement.
>DELETE authors
>WHERE au_id = '409-56-7088'
>
>-- Set a variable to the error value for
>-- the DELETE statement.
>SELECT @del_error = @@ERROR
>
>-- Execute the INSERT statement.
>INSERT authors
>   VALUES('409-56-7008', 'Bennet', 'Abraham', '415 658-9932',
>   '6223 Bateman St.', 'Berkeley', 'CA', '94705', 1)
>-- Set a variable to the error value for
>-- the INSERT statement.
>SELECT @ins_error = @@ERROR
>
>-- Test the error values.
>IF @del_error = 0 AND @ins_error = 0
>BEGIN
>   -- Success. Commit the transaction.
>   PRINT "The author information has been replaced"
>   COMMIT TRAN
>END
>ELSE
>BEGIN
>   -- An error occurred. Indicate which operation(s) failed
>   -- and roll back the transaction.
>   IF @del_error <> 0
>      PRINT "An error occurred during execution of the DELETE
>      statement."
>
>   IF @ins_error <> 0
>      PRINT "An error occurred during execution of the INSERT
>      statement."
>
>   ROLLBACK TRAN
>END

>
>This one is probably preffered method, right?