SAVE TRAN

USE AdventureWorks;

GO

IF EXISTS (SELECT name FROM sys.objects

WHERE name = N'SaveTranExample')

DROP PROCEDURE SaveTranExample;

GO

CREATE PROCEDURE SaveTranExample

@InputCandidateID INT

AS

-- Detect if the procedure was called

-- from an active transaction and save

-- that for later use.

-- In the procedure, @TranCounter = 0

-- means there was no active transaction

-- and the procedure started one.

-- @TranCounter > 0 means an active

-- transaction was started before the

-- procedure was called.

DECLARE @TranCounter INT;

SET @TranCounter = @@TRANCOUNT;

IF @TranCounter > 0

-- Procedure called when there is

-- an active transaction.

-- Create a savepoint to be able

-- to roll back only the work done

-- in the procedure if there is an

-- error.

SAVE TRANSACTION ProcedureSave;

ELSE

-- Procedure must start its own

-- transaction.

BEGIN TRANSACTION;

-- Modify database.

BEGIN TRY

DELETE HumanResources.JobCandidate

WHERE JobCandidateID = @InputCandidateID;

-- Get here if no errors; must commit

-- any transaction started in the

-- procedure, but not commit a transaction

-- started before the transaction was called.

IF @TranCounter = 0

-- @TranCounter = 0 means no transaction was

-- started before the procedure was called.

-- The procedure must commit the transaction

-- it started.

COMMIT TRANSACTION;

END TRY

BEGIN CATCH

-- An error occurred; must determine

-- which type of rollback will roll

-- back only the work done in the

-- procedure.

IF @TranCounter = 0

-- Transaction started in procedure.

-- Roll back complete transaction.

ROLLBACK TRANSACTION;

ELSE

-- Transaction started before procedure

-- called, do not roll back modifications

-- made before the procedure was called.

IF XACT_STATE() <> -1

-- If the transaction is still valid, just

-- roll back to the savepoint set at the

-- start of the stored procedure.

ROLLBACK TRANSACTION ProcedureSave;

-- If the transaction is uncommitable, a

-- rollback to the savepoint is not allowed

-- because the savepoint rollback writes to

-- the log. Just return to the caller, which

-- should roll back the outer transaction.

-- After the appropriate rollback, echo error

-- information to the caller.

DECLARE @ErrorMessage NVARCHAR(4000);

DECLARE @ErrorSeverity INT;

DECLARE @ErrorState INT;

SELECT @ErrorMessage = ERROR_MESSAGE();

SELECT @ErrorSeverity = ERROR_SEVERITY();

SELECT @ErrorState = ERROR_STATE();

RAISERROR (@ErrorMessage, -- Message text.

@ErrorSeverity, -- Severity.

@ErrorState -- State.

);

END CATCH

GO