When select from a derby view will the query used to create the view be executed again?

Question

I noticed that when I change underlying table , the result of selecting from the view will be different,but I wonder it is because the view update every time table changes or every time being selected from?

Answer 1

is because the view update every time table changes or every time being selected from?

The latter, i.e. every time you select from the view, the underlying tables will be re-queried, as though you'd run the view's SQL directly.

Some database systems (but not, I suspect, Derby), have the concept of the "materialized view" which is a snapshot of the view's query results, which may be updated when the data in the underlying tables changes.