Chapter 18. Packages

A package is a grouping or packaging together of PL/SQL code elements. 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 the package so powerful and important? Consider their advantages:

Easier enhancement and maintenance of applications

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 it is 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.

Improved 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 of queries by caching static ...

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