The SET VERIFY ON command is related to how SQL*Plus and SQL Developer display information about substitution variables:
A . It displays values for variables created by the DEFINE command: When VERIFY is set to ON, SQL*Plus and SQL Developer will display the old and new values of a substitution variable when it is redefined using the DEFINE command or when a new value is provided for it during the session.
B . It can be used in SQL Developer and SQL*Plus: While traditionally associated with SQL*Plus, the SET VERIFY command is also supported in SQL Developer, allowing you to control the display of substitution variable values in both environments.
Reference: Oracle SQL*Plus User's Guide and Reference, especially the section on the SET command and substitution variables.
