Oracle PL/SQL for DBAs

The PL/SQL Character Set

A PL/SQL program consists of a sequence of statements, each made up of one or more lines of text. The precise characters available to you will depend on what database character set you’re using. For example , Table 1-1 illustrates the available characters in the US7ASCII character set .

Table 1-1. Characters available to PL/SQL in the US7ASCII character set

Type	Characters
Letters	A-Z, a-z
Digits	0–9
Symbols	~ ! @ # $ % * ( ) _ - + = | : ; " ' < > , . ? / ^
Whitespace	Tab, space, newline, carriage return

Every keyword, operator, and token in PL/SQL is made from various combinations of characters in this character set. Now you just have to figure out how to put them all together!

Keep in mind that PL/SQL is a case-insensitive language. That is, it doesn’t matter how you type keywords and identifiers; uppercase letters are treated the same way as lowercase letters unless surrounded by delimiters that make them a literal string. By convention, the authors of this book prefer uppercase for built-in language keywords and lowercase for programmer-defined identifiers.

A number of these characters—both singly and in combination with other characters—have a special significance in PL/SQL. Table 1-2 lists these special symbols.

Table 1-2. Simple and compound symbols in PL/SQL

Symbol	Description
;	Semicolon: terminates declarations and statements
%	Percent sign: attribute indicator (cursor attributes like %ISOPEN and indirect declaration attributes like ...