Learning Oracle PL/SQL

2.8. Code Formatting: Requirements and Guidelines

As you begin to write your own code, you will have many questions about the best approach to capitalization, indentation, spacing, and other aspects of programming style. This section lists some of the features of the language in this area, and should help you get started with good habits.

2.8.1. Upper- or Lowercase?

PL/SQL is case-insensitive (except for the values of literal strings). That means you can type keywords and identifiers in uppercase or lowercase or mixed-case—it doesn't make any difference. So all of these statements are identical:

favorite_flavor VARCHAR2(20);
Favorite_Flavor varchar2(20);
fAvOrItE_flaVOR vArCHAr(20);

O'Reilly's PL/SQL books generally recommend putting reserved words in all upper-case and programmer-supplied identifiers in all lowercase, as in the first line of the previous code. I have to admit that this seemed at first strange and inconvenient to me. Over time, though, I learned the merits of this convention—it lets my eye skate very rapidly over the contrasting type styles to find the essential information in the code.

2.8.2. Spacing and Line Breaks

You'll sometimes hear programmers talk of whitespace in their programs. Whitespace consists of spaces, tabs, and/or line breaks. PL/SQL allows any amount of whitespace to separate keywords and identifiers. The declaration:

favorite_flavor VARCHAR2(20);

is completely equivalent to:

   favorite_flavor VARCHAR2(20);

and also to the ludicrous: ...