Date format is not changed after executing alter system
<p>The database is Oracle 11g2 Express. I executed <code>alter system set NLS_DATE_FORMAT = "DD/MM/RRRR" SCOPE=SPFILE;</code> , and then I made a query : <code>select hire_date from employees;</code> but the format displayed is still DD/MM/RR ! So how to change <code>nls_date_format</code> permanently ?</p>