Virtual columns

Maarten wrote a post on Virtual Columns in the oracle database. I read a blogpost on preventing people issuing SELECT * on a table. This was done in a different database, so I decided to try it out in my Oracle Database.
First I create a simple table:

create table demo.emp_nuke
  empno  number(4) not null
, ename  varchar2(10)
, sal    number(7,2)
, deptno number(2)
, blowitup number generated always as (1/0) virtual

Virtual Private Database…

Some time ago I was asked to assist in fixing or at least finding the cause of a performance problem. The application ran fine until the Virtual Private Database (VPD) policy was applied. Oracle claims there should be near zero impact on your application when you implement VPD, then how is this possible?

First of all, the policy applied was a rather complex one. A complex query should be executed to determine if the current (more...)