oracle - how to handle the text entered from the keyboard pl sql -

how manage text input keyboard using command prompt in pl / sql oracle. want verified if text inserted empty or insert more lines

-i use line address retrieve data keyboard

set serveroutput on

accept my_var varchar(256) prompt 'insert number:',

the thing know sql plus can prompt user parameter value.. let user using sqlplus type in text. i'm not sure if that's want meant...

you can adding &.

so

select person.name person age = &age