Learning Oracle PL/SQL

2.1. PL/Lingo

While some programming languages look like Einstein's scribbles, Oracle PL/SQL uses specific, easy to understand keywords (reserved words in the language) to identify the different parts of a PL/SQL program. To indicate the beginning of the exception section in your program, for example, you use the

EXCEPTION

keyword. To show that you have ended your program, you use the (you guessed it!)

END;

keyword.

The English-like nature of PL/SQL is just one aspect of the language that makes it relatively easy to learn. However, given the fact that PL/SQL lives with one foot in the database and one foot in the procedural world, even the English terminology may be unfamiliar to you. Here are a few concepts and terms you'll want to know up front.

Keyword

This book uses the term keyword to mean a word that the language recognizes.^[1] In PL/SQL, keywords include BEGIN, END, IF, and RETURN.

^[1] PL/SQL's keywords tend to expand with each new release. You can find a complete list in the "Reserved Words" appendix of the PL/SQL User's Guide and Reference supplied by Oracle for the version of the database you're using.

Identifier

A name for something such as a variable or a stored procedure. Some are predefined by the language, and some you invent. Some examples of invented identifiers: printme, balance_in_$, book2.

Datatype

A name for a class of values. PL/SQL's built-in datatypes include NUMBER, DATE, and VARCHAR2 (that means text).

Variable

A "container," named with an ...