This book uses the following typographical conventions to mark certain portions of text: new terms, foreign phrases, and other important passages are emphasized in italics . Everything that represents input or output of the computer, in particular commands, program code, and screen output, is shown in a monospaced font ( example ). Within such passages, italics ( example ) indicate placeholders; you must insert an actual value instead of the placeholder. On occasion, parts of program code are emphasized in bold face ( example ), if they have been added or changed since the preceding example.

The following conventions are used in the synopsis of a command: brackets ( [ and ] ) indicate optional parts. (In the synopsis of a Tcl command, question marks ( ? ) are used instead, as is usual in Tcl.) Braces ( { and } ) and vertical lines ( | ) indicate that you must choose one alternative. Dots ( ... ) mean that the preceding element can be repeated.

Where it enhances the clarity, SQL commands are preceded by the prompt => , and shell commands are preceded by the prompt $ . Normally, prompts are not shown, though.

An administrator is generally a person who is in charge of installing and running the server. A user could be anyone who is using, or wants to use, any part of the PostgreSQL system. These terms should not be interpreted too narrowly; this book does not have fixed presumptions about system administration procedures.