>>>My UI is built in such a way that only one row can be deleted from the parent table anyway. But I will see if I still should add your code that check and raises the error.
>>>
>>>As far as my original question. Are you saying that if any UPDATE CHILD in my trigger fails the SQL Server will raise an error anyways? What if update of CHILD 3 fails, will SQL Server roll back the changes to the CHILD 1 and 2?
>>>
>>>Thank you.
>>
>>The best way is to try and test. Without testing I'm guessing that none of the updates will take place is one of the updates fail.
>
>I agree with you; this is the right way. I just need to learn how to make one of the child updates to fail :). Thank you.

Very simple. Add for now updating one of the fields that doesn't allow NULL with NULL.