Oracle PL/SQL Programming, 6th Edition

Chapter 3. Language Fundamentals

Every language—whether human or computer—has a syntax, a vocabulary, and a character set. In order to communicate within that language, you have to learn the rules that govern its usage. Many of us are wary of learning a new computer language. Change is often scary, but in general programming languages are very simple, and PL/SQL is no exception. The difficulty of conversing in languages based on bytes is not with the language itself, but with the compiler or computer with which we are having the discussion. Compilers are, for the most part, rather dull-witted. They are not creative, sentient beings. They are not capable of original thought. Their vocabulary is severely limited. Compilers just happen to think their dull thoughts very, very rapidly—and very inflexibly.

If I hear someone ask “gottabuck?” I can readily interpret that sentence and decide how to respond. On the other hand, if I instruct PL/SQL to “gimme the next half-dozen records,” I will not get very far in my application. To use the PL/SQL language, you must dot your i’s and cross your t’s—syntactically speaking. So, this chapter covers the fundamental language rules that will help you converse with the PL/SQL compiler—the PL/SQL block structure, character set, lexical units, and PRAGMA keyword.

PL/SQL Block Structure

In PL/SQL, as in most other procedural languages, the smallest meaningful grouping of code is known as a block. A block is a unit of code that provides execution and scoping ...