There have been mistakes arising regarding single and multiple rows from wrong coding by developers. They make such critical mistakes because of their wrong thinking that the trigger code performs once in a row and it is affected by the whole statement rather than only once for the entire statement. Even Oracle coding can have problems in the correct modification of data. This problem can be dealt with on the SQL Server 2000.  If your application needs that you can never put more than one row into a table, at a time, you can restrict the table by adding the code to the trigger that can be inserted. You can read more on this interesting article on Howto.fm