With HTML safely out of the way, we can turn our attention to the second half of our web development platform: PL/SQL, Oracle’s proprietary extension to structured query language (SQL). The PL stands for Procedural Language, since PL/SQL is used to create procedural constructs (loops, variables, etc.) on top of the relational constructs of SQL.
Although it has some object-oriented features, PL/SQL is based largely on Ada, a structured programming language used heavily by the Department of Defense. As such, PL/SQL has more in common with languages like C, Pascal, or COBOL than it does with C++ or Java. Although it follows an older design model (structured versus object), PL/SQL has the advantages of being easy to learn, tightly integrated to the Oracle database, and extensible. If you know how to write a SQL script and know at least one 3GL language, you can learn to develop useful PL/SQL programs in just a few hours.
In the next three sections we’ll cover what you need to know to start developing in PL/SQL: how to structure a PL/SQL program, how to fill in its major programming constructs, and how to create reusable modules called packages. In the last section we’ll look at two third-party tools, TOAD and PL/Formatter, that make PL/SQL development much more enjoyable and productive.
There is much more to say about the PL/SQL language. For complete information, see Steven Feuerstein and Bill Pribyl’s Oracle PL/SQL Programming (O’Reilly & Associates).