SQL*Plus contains a large number of internal variables that control various aspects of the way the product operates. The SET command is used to change these settings to suit your preferences. The number of settings is quite large, so for convenience I’ve divided them into the following categories:
Report output and format settings
Substitution variable settings
Large object settings
Tuning and timing settings
Database administration settings
The following sections describe the settings available in each of these categories.
The largest group of SQL*Plus settings exists to control the way data is formatted, displayed, and output for a report. These settings control such things as the number of lines on a page, the line length, whether or not tab characters are used to format the output, and so forth. The following list briefly describes each of these settings:
Controls the text used to separate columns of data.
Turns the embedded report feature on or off.
Controls the character used to mark a line break in a column heading.
Controls whether or not column headings are displayed when selecting data.
Specifies the maximum line width.
The maximum row length SQL*Plus can handle.
Controls what SQL*Plus prints when advancing to a new page.
Contains the text SQL*Plus displays for any null values returned by a query. ...