Advanced Oracle PL/SQL Programming with Packages

Chapter 12. PLVio: Reading and Writing PL/SQL Source Code

The PLVio (PL/Vision Input/Output) package consolidates all the logic required to read from and write to repositories for PL/SQL source code. The PLVio package supports operating system files (as of Release 2.3), database tables, strings, and PL/SQL tables as both input and output sources. It hides all of the complexities of this I/O from users of the PLVio package. By relying on PLVio, other PL/Vision packages, such as PLVhlp and PLVcase, can pass on support for these varying repositories with minimal effort and maximum flexibility.

PLVio is a large package with many different elements. Generally, PLVio activity breaks down into the following areas:

• Set and manage the source repository, including the WHERE clause of the SQL statement used to define the source if it is a database table. Among other things, you can initialize and close the source.

• Set and manage the target repository. You can display, close, and clear the target.

• Read from the source and write to the target. You can even transfer the contents of the source repository to the target in a single step with the src2trg procedure.

• Save and restore repository settings. This is useful when you are using PLVio simultaneously in different contexts.

• Trace PLVio activity with a package window.

You can also use PLVio to manipulate text that is not PL/SQL source. Indeed, you can use PLVio to more easily write text out to operating system files (an interface to PLVfile ...