title: how to handle the text entered from the keyboard pl sql
body: <p>how to manage the text input from the keyboard using the command prompt in pl / sql Oracle.
  I want to verified if the text inserted  is empty or insert more lines</p>
  
  <p>-I use this line Address to retrieve a data from the keyboard</p>
  
  <p><strong>set serveroutput on</strong> </p>
  
  <p><strong>accept my_var  varchar(256) prompt 'insert your Number:',</strong></p>