Everybody who chooses to write PL/SQL programs does so to work with the contents of an Oracle database. It is, therefore, no surprise that you will need to know how to “get around” the Oracle database where your code is going to run. You will want to examine the data structures (tables, columns, sequences, user-defined types, etc.) in the database, as well as the signatures of any existing stored programs you will be invoking. You will probably also need to know something about the actual contents (columns, constraints, etc.) of the tables.
There are two distinct approaches you can take to database navigation:
Use an IDE (integrated development environment, a fancy name for a fancy editor) like Toad, SQL Developer, PL/SQL Developer, SQL Navigator, etc. They all offer visual browsers which support point and click navigation.
Run scripts in a command-line environment like SQL*Plus that queries the contents of data dictionary views like ALL_OBJECTS or USER_OBJECTS (demonstrated later in this chapter).
I strongly recommend that you use a graphical IDE. If you have been around Oracle long enough, you might be addicted to and fairly productive with your scripts. For the rest of us, a graphical interface is much easier to work with and understand—and much more productive—than scripts.
Chapter 20 also offers examples of using several data dictionary views for working with your PL/SQL code base.