Oracle PL/SQL Programming, 6th Edition

Chapter 18. Packages

A package is a grouping or packaging together of elements of PL/SQL code into a named scope. Packages provide a structure (both logically and physically) in which you can organize your programs and other PL/SQL elements such as cursors, TYPEs, and variables. They also offer significant, unique functionality, including the ability to hide logic and data from view and to define and manipulate “global” or session-persistent data.

Why Packages?

The package is a powerful and important element of the PL/SQL language. It should be the cornerstone of any application development project. What makes packages so powerful and important? Consider their advantages. With packages, you can:

Enhance and maintain applications more easily

As more and more of the production PL/SQL code base moves into maintenance mode, the quality of PL/SQL applications will be measured as much by the ease of maintenance as by overall performance. Packages can make a substantial difference in this regard. From data encapsulation (hiding all calls to SQL statements behind a procedural interface to avoid repetition), to enumerating constants for literal or “magic” values, to grouping together logically related functionality, package-driven design and implementation lead to reduced points of failure in an application.

Improve overall application performance

By using packages, you can improve the performance of your code in a number of ways. Persistent package data can dramatically improve the response time ...