Hello!
From “Oracle Database Application Developer’s Guide - Object-Relational Features”:
Note: You can create views of types that are non-instantiable. A non-instantiable type cannot have instances, so ordinarily there would be no point in creating an object view of such a type. However, a non-instantiable type can have subtypes that are instantiable. The ability to create object views of non-instantiable types enables you to base an object view hierarchy on a type hierarchy that contains a non-instantiable type.
What should be the exact syntax for such view creation? The problem is that for any query, that I'm trying to use for the actual view definition, I'm getting “ORA-22826: cannot construct an instance of a non instantiable type”. Even if I try something like “select … from dual where 1=0”.
I was thinking that maybe there is some special syntax for such view creation (something like
create view {object_view} of {object_type}
without actual query), but wasn't able to find anything related to this problem.
Found old post from 2004 describing exactly the same problem, but no helpful info in it unfortunately…