social networking website.. need reply soon

Question

hello friends,

i have to make social networking website like orkut and facebook..'

 i want that username and password should be checked from aspdb and all other things profile,community,scraps etc should be from custom table(which i wl add to aspdb database)

is it possible? and to which table of aspdb i use to create relationship with other customized table(scraps,friends,community) etc