Oracle PL/SQL Programming, 5th Edition

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:

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 they are 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 of queries by caching static data, thereby avoiding repeated queries of the same information. Oracle’s memory management also optimizes access to code defined in packages (see Chapter 24 for more details).

Shore up application or built-in weaknesses

It is quite straightforward to construct a package on top of existing functionality where there are drawbacks. (Consider, for example, the UTL_FILE and DBMS_OUTPUT built-in packages in which crucial functionality ...