sql DELETE trigger won't rollback - sql

Question

The trigger is supposed to rollback if the statement in the SELECT exists. The thing is, it doesn't. When I only run the SELECT from the trigger, it shows that a row exists. But when I try DELETE with the same values as I have hard coded in the trigger, the trigger fires but it does not do a rollback. Anyone got any ideas what might be wrong?
CREATE TRIGGER trg_del ON Projektbefattningar
FOR DELETE
AS
SELECT #befNr = Befattningsnr, #pNr = pNr, #EtappNr = Etappnr FROM deleted
-- Not currently using these. Using hard coded values to illustrate my problem
IF EXISTS (
SELECT *
FROM projektbefattningar
WHERE Befattningsnr = 2 AND pNr = 1 and Etappnr = 1 AND Anställningsnr is not null
)
BEGIN
RAISERROR('Could not delete, Anställningsnr is not null', 16, 1)
--THROW 50001, 'Could not delete, Anställningsnr is not null', 1;
ROLLBACK TRANSACTION;
END
GO

Answer 1

When you use FOR DELETE you consider that this TRIGGER will fired after the delete statement is complete. To Verify a condition before DELETE you need to use INSTEAD OF DELETE. Your Trigger declaration will be:
CREATE TRIGGER trg_del ON Projektbefattningar
INSTEAD OF DELETE
AS
Now To Confirm your delete statement you need to include the delete alghouth it will not be deleted.
The final procedure will be like this:
CREATE TRIGGER trg_del ON Projektbefattningar
INSTEAD OF DELETE
AS
SELECT #befNr = Befattningsnr, #pNr = pNr, #EtappNr = Etappnr FROM deleted
-- Not currently using these. Using hard coded values to illustrate my problem
IF EXISTS (
SELECT *
FROM projektbefattningar
WHERE Befattningsnr = 2 AND pNr = 1 and Etappnr = 1 AND Anställningsnr is not null
)
BEGIN
RAISERROR('Could not delete, Anställningsnr is not null', 16, 1)
--THROW 50001, 'Could not delete, Anställningsnr is not null', 1;
ROLLBACK TRANSACTION;
END
ELSE
BEGIN
DELETE FROM YourTableToDelete Where idOfYourTable in ( Select idOfYourTable from Deleted )
END
GO

Answer 2

Try this
CREATE TRIGGER trg_del ON Projektbefattningar
FOR DELETE
AS
SELECT #befNr = Befattningsnr
,#pNr = pNr
,#EtappNr = Etappnr
FROM deleted
-- Not currently using these. Using hard coded values to illustrate my problem
IF EXISTS (
SELECT 1
FROM deleted
WHERE Befattningsnr = 2
AND pNr = 1
AND Etappnr = 1
AND Anställningsnr IS NOT NULL
)
BEGIN
RAISERROR (
'Could not delete, Anställningsnr is not null'
,16
,1
)
--THROW 50001, 'Could not delete, Anställningsnr is not null', 1;
ROLLBACK TRANSACTION;
END
GO