I\'m trying to create a simple trigger using TSQL (or SQL Server 2008). The problem is: my current trigger is updating the entire table. This was fine for a while, but now t
You need to join the Inserted pseudo table in your UPDATE statement. Always be aware that SQL Server fires the trigger once per statement and that statement can very well modify/insert multiple rows at once - so your Inserted table quite likely will contain more than one row - just need to keep that in mind when you write your trigger.
Try something like this:
CREATE TRIGGER trig_MyPplUpdate
ON [Persons]
FOR INSERT
AS
UPDATE dbo.Persons
SET MyFile = NULL
WHERE Len(MyFile) < 60
AND PersonID IN (SELECT DISTINCT PersonID FROM Inserted)
or use whatever unique column (your primary key) you have to get exactly those rows that have been inserted.