Convert date to number

Hi,

I need to append the date to a unique number for each insert according to the date at which the data is being insert.

Is there a way to convert sysdate to say 05112007? The nearest i can get is '05/11/2007' by using

select to_date(sysdate,'dd-mm-yyy') from dual

In any case, is there such a thing called a date sequence?

Thanks!

select to_char(sysdate,'DDMMYYYY') from dual