Sets a system variable to alter the SQL*Plus environment settings for your current session, for example, to:
customize HTML formatting
enable or disable the printing of column headings
set the number of lines per page
set the display width for data
SET system_variable value
where system_variable and value represent one of the clauses shown in the SET System Variable Summary table following.
SQL*Plus maintains system variables (also called SET command variables) to enable you to set up a particular environment for a SQL*Plus session. You can change these system variables with the SET command and list them with the SHOW command.
SET ROLE and SET TRANSACTION are SQL commands (see the Oracle Database SQL Language Reference for more information). When not followed by the keywords TRANSACTION or ROLE, SET is assumed to be a SQL*Plus command.