I wonder if it's possible to have some sort of controlled de-normalization. Like, the ability to create a read-only column whose values mimic that of a column i

I wonder if it's possible to have some sort of controlled de-normalization. Like, the ability to create a read-only column whose values mimic that of a column in some other table. A "view column" if you will. I would definitely opt for that as a "real-world" practice.