Oracle Advanced PL/SQL Developer Professional Guide

VPD implementation—outline and components

The development steps of VPD implementation is demonstrated in the flowchart as follows:

• Creation of an application context: The application context is a collection of variables whose values, once set, remain the same and are available in the same session. The variables are known as attributes. Each session accessing the same application context attributes can have different values.
• Create the context key and value: Create the trusted program to set the context using DBMS_SESSION.SET_CONTEXT. During the creation of the context, Oracle does not verify the existence of the program being specified. It relies on the trust of the user to create and use a program with the same name to set the context attributes. ...