Can I Use Database Blocks In My oracle 9i Forms Application

hello

i am very new to forms 9i development environment. i was working on vb 6.0 and vb.net.
can i use base table blocks in my application ?. why i doubt is if my database grows to 5,00,000 records in a year will there be any performance problems ?

is it the professsional way of developing applications in forms using base table blocks ?

or shall i use only the control blocks ?

please any guide me to the right direction .. i hope there is light in my search ..ha ha ..

thanks in adv.

Mohan G

hi to all dba's i want about apps funtional