Rollback Transaction when concurrency check fails - sql-server

Question

I have a stored procedure which does a lot of probing of the database to determine if some records should be updated
Each record (Order) has a TIMESTAMP called [RowVersion]
I store the candidate record ids and RowVersions in a temporary table called #Ids
DECLARE #Ids TABLE (id int, [RowVersion] Binary(8))
I get the count of candidates with the the following
DECLARE #FoundCount int
SELECT #FoundCount = COUNT(*) FROM #Ids
Since records may change from when i SELECT to when i eventually try to UPDATE, i need a way to check concurrency and ROLLBACK TRANSACTION if that check fails
What i have so far
BEGIN TRANSACTION
-- create new combinable order group
INSERT INTO CombinableOrders DEFAULT VALUES
-- update orders found into new group
UPDATE Orders
SET Orders.CombinableOrder_Id = SCOPE_IDENTITY()
FROM Orders AS Orders
INNER JOIN #Ids AS Ids
ON Orders.Id = Ids.Id
AND Orders.[RowVersion] = Ids.[RowVersion]
-- if the rows updated dosnt match the rows found, then there must be a concurrecy issue, roll back
IF (##ROWCOUNT != #FoundCount)
BEGIN
ROLLBACK TRANSACTION
set #Updated = -1
END
ELSE
COMMIT
From the above, i'm filtering the UPDATE with the stored [RowVersion] this will skip any records that have since been changed (hopefully)
However i'm not quite sure if i'm using transactions or optimistic concurrency in regards to TIMESTAMP correctly, or if there are better ways to achieve my desired goals

Answer 1

It's difficult to understand what logic you are trying to implement.
But, if you absolutely must perform several non-atomic actions in a procedure and make sure that the whole block of code is not executed again while it is running (for example, by another user), consider using sp_getapplock.
Places a lock on an application resource.
Your procedure may look similar to this:
CREATE PROCEDURE [dbo].[YourProcedure]
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
BEGIN TRANSACTION;
BEGIN TRY
DECLARE #VarLockResult int;
EXEC #VarLockResult = sp_getapplock
#Resource = 'UniqueStringFor_app_lock',
#LockMode = 'Exclusive',
#LockOwner = 'Transaction',
#LockTimeout = 60000,
#DbPrincipal = 'public';
IF #VarLockResult >= 0
BEGIN
-- Acquired the lock
-- perform your complex processing
-- populate table with IDs
-- update other tables using IDs
-- ...
END;
COMMIT TRANSACTION;
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION;
END CATCH;
END

Answer 2

When you SELECT the data, try using HOLDLOCK and UPDLOCK while inside of an explicit transaction. It's going to mess with the concurrency of OTHER transactions but not yours.
http://msdn.microsoft.com/en-us/library/ms187373.aspx