When you create a new field in your database, 4D allows you to choose to map NULL value to blank values or not. Starting from 4D v19 R4, in new projects, 4D will no longer by default map the NULL value to an empty value.
4D v19 R4 is shipped with a new ORDA concept: Aliases. They are the logical and complementary continuation of computed attributes.
This blog post explains what aliases are and highlights their advantages, especially when to use one or the other… or both.