Updating schema

Scenario: user gets an update on the app which includes a schema-update. The schema-update adds a new column (fAnswer: string). The field will be null. The database-update succeeds. However, delphi will not work as the initial content is null. I could use nullable<>. But before doing so I was just wondering if there is another way... 

What would be the best approach when one wants to update the database schema in a later version of an application?

I'm not sure I understand the problem? You mention that the database-update succeeds, but Delphi will not work because initial content is null. What exactly do you mean, can you describe in a more detailed way.

Usually the database update mechanism of Aurelius won't allow you to add not-null columns to the database. But if you say you are adding a nullable column, it will just add that column to the table and everything should work fine.