Book Image

Oracle Advanced PL/SQL Developer Professional Guide

By : Saurabh K. Gupta
Book Image

Oracle Advanced PL/SQL Developer Professional Guide

By: Saurabh K. Gupta

Overview of this book

PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension language for SQL and the Oracle relational database. Server-side PL/SQL is stored and compiled in the Oracle Database and runs within the Oracle executable. With this guide Oracle developers can work towards accomplishing Oracle 11g Advanced PL/SQL Professional certification, which is the second milestone for developers working at the Associate level. The Oracle Advanced PL/SQL Developer Professional Guide helps you master advanced PL/SQL concepts. Besides the clear and precise explanation on advanced topics, it also contains example code and demonstrations, which gives a sense of application and usage to readers.The book gives a deep insight that will help transform readers from mid-level programmers to professional database developers. It aims to cover the advanced features of PL/SQL for designing and optimizing PL/SQL code.This book starts with an overview of PL/SQL as the programming database language and outlines the benefits and characteristics of the language. The book then covers the advanced features that include PL/SQL code writing using collections, tuning recommendations using result caching, implementing VPD to enforce row level security, and much more. Apart from programming, the book also dives deep into the usage of the development tool SQL Developer, employing best practices in database environments and safeguarding the vulnerable areas in PL/SQL code to avoid code injection.
Table of Contents (22 chapters)
Oracle Advanced PL/SQL Developer Professional Guide
Credits
Foreword
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Policy utilities—refresh and drop


Policy utility activities such as refreshing or dropping can be done through DBMS_RLS package subprograms. Refreshing a policy pushes an enabled VPD protocol to inherit the latest changes done to the policy and its dependents. Policy refresh is required when the underlying referenced objects of the policy undergo changes. So as to invalidate its dependent objects operationally during the policy refresh process, all the cached statements associated with the policy are parsed again.

Notice that a disabled VPD policy cannot be refreshed.

The subprogram requires the policy owner, the table or view name, and the policy name as the input parameters:

SQL> EXEC DBMS_RLS.REFRESH_POLICY('ORADEV','EMPLOYEES','EMP_DEPT_20');

PL/SQL procedure successfully completed.

Dropping a policy lifts the data restriction and full data is visible to all the users. Like REFRESH_POLICY, the dropping subprogram also requires the policy owner, the table or view name, and the policy...