I would give the work to Oracle
First of all, in Oracle if you insert into a DATE column,
and your
date literal is in the
default data format (which is usually DD-MON-YY) then you can simply send the string to Oracle like this:
Second, you can use Oracle's to_date function:
Yes the above is a bit crazy with the YYDDMM, but the point is made
Third, to add 5 days why not give it to Oracle?