Add custom properties to .tt POCO classes lost on updating model <p>I've created a 3-tier web application using EntityFramework Database first approach. I need to add custom properties to POCO classes that do not exist in the database. However when I update my edmx and Run Custom Tool for the tt file, my classes get refreshed as per the database and I lose the custom properties I created. </p> <p>I need such custom properties in my web application only, and I can't add them to the Database. Is there a way to refresh the POCO classes without losing the custom properties? </p>