Virtual Column in Oracle

Oracle has introduced new feature in version 11 ie. Virtual column. Virtual column values are not stored on disk. They are generated at runtime using their associated expression.

Lets have a look how to create a table with Virtual Column 

CREATE TABLE testvirtual
(
   id1   NUMBER (10)
 , id2   NUMBER (10)
 , id3   NUMBER (10) GENERATED ALWAYS AS (id1 + id2) VIRTUAL
);
Virtual keyword is optional.