Let's say I have an SQL statement that's syntactically and semantically correct so it executes.
In Management Studio (or any other query tool) how can I test SQL statements, and if I notice that they broke something, rollback (in a separate query?)
This question is related to
sql
tsql
transactions
The easisest thing to do is to wrap your code in a transaction, and then execute each batch of T-SQL code line by line.
For example,
Begin Transaction
-Do some T-SQL queries here.
Rollback transaction -- OR commit transaction
If you want to incorporate error handling you can do so by using a TRY...CATCH BLOCK. Should an error occur you can then rollback the tranasction within the catch block.
For example:
USE AdventureWorks;
GO
BEGIN TRANSACTION;
BEGIN TRY
-- Generate a constraint violation error.
DELETE FROM Production.Product
WHERE ProductID = 980;
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESSAGE() AS ErrorMessage;
IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END CATCH;
IF @@TRANCOUNT > 0
COMMIT TRANSACTION;
GO
See the following link for more details.
http://msdn.microsoft.com/en-us/library/ms175976.aspx
Hope this helps but please let me know if you need more details.
I want to add a point that you can also (and should if what you are writing is complex) add a test variable to rollback if you are in test mode. Then you can execute the whole thing at once. Often I also add code to see the before and after results of various operations especially if it is a complex script.
Example below:
USE AdventureWorks;
GO
DECLARE @TEST INT = 1--1 is test mode, use zero when you are ready to execute
BEGIN TRANSACTION;
BEGIN TRY
IF @TEST= 1
BEGIN
SELECT *FROM Production.Product
WHERE ProductID = 980;
END
-- Generate a constraint violation error.
DELETE FROM Production.Product
WHERE ProductID = 980;
IF @TEST= 1
BEGIN
SELECT *FROM Production.Product
WHERE ProductID = 980;
IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESSAGE() AS ErrorMessage;
IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END CATCH;
IF @@TRANCOUNT > 0 AND @TEST = 0
COMMIT TRANSACTION;
GO
I want to add a point that you can also (and should if what you are writing is complex) add a test variable to rollback if you are in test mode. Then you can execute the whole thing at once. Often I also add code to see the before and after results of various operations especially if it is a complex script.
Example below:
USE AdventureWorks;
GO
DECLARE @TEST INT = 1--1 is test mode, use zero when you are ready to execute
BEGIN TRANSACTION;
BEGIN TRY
IF @TEST= 1
BEGIN
SELECT *FROM Production.Product
WHERE ProductID = 980;
END
-- Generate a constraint violation error.
DELETE FROM Production.Product
WHERE ProductID = 980;
IF @TEST= 1
BEGIN
SELECT *FROM Production.Product
WHERE ProductID = 980;
IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESSAGE() AS ErrorMessage;
IF @@TRANCOUNT > 0
ROLLBACK TRANSACTION;
END CATCH;
IF @@TRANCOUNT > 0 AND @TEST = 0
COMMIT TRANSACTION;
GO
Source: Stackoverflow.com