string.Empty is not the same as Nothing (or null). By default the properties you mention are null and not string.Empty. Hence removing the explicit assignations to string.Empty resolved the problem.

Deciding which database technology to use for your system can be a complex task and, as such, there are no right or wrong answers to your question. Much depends on the requirements you...

Anders is quite correct - a trigger is not an option.

You need to write a stored procedure that is run say, every 5 minutes, using a SQL Server job. Jobs are easy to use...