Need Help Checking To See If More Than 1 Record Updated.

I am trying to write a trigger that, on an update, will check to see if more than one record is being updated. If more than one record is being updated, rollback the transaction and print a message. If not, then commit the transaction and print an OK message.

My problem is I am having troubles writing this trigger. I will post my SQL trigger code so far.

I am new with Triggers, so any help or advice is appreciated.


Code:

CREATE TRIGGER trgPaperCheck
ON BOOK
AFTER UPDATE
AS
IF UPDATE(Paperback)
BEGIN
DECLARE @count AS INT
SELECT @count = COUNT(Paperback)
FROM Book
IF @count > 1
BEGIN
PRINT('Only one Book record can be updated at a time!')
ROLLBACK TRANSACTION
END
ELSE IF @count =1
BEGIN
PRINT('Paperback Updated')
COMMIT TRANSACTION
END
END