Most software today is very much like an Egyptian pyramid with millions of bricks piled on top of each other, with no structural integrity, but just done by brute force and thousands of slaves. Alan Kay
The to_date function convert the string format date to the date format. When the developer want fetch the date format from the string, they can use to_date function. The DUAL table is a special one-row, one-column table present by default in Oracle and other database installations. The sysdate returns the current date from the oracle database server.
select to_date('2013/12/10', 'yyyy/mm/dd') from dual;