Table secure problem.

Hi.

(Sorry for my english -I'am not a nativ speaker)

I have some problem. I show it with example:

I have base names for e.g. "db".
I have also user "joe" (in pg_shadow). Joe is not a superuser or somethink
like that his is normal user.
He connect to db. He can't do anything because I don't give him any grants,
but he can create new tables. and ther is a problem. He could create table
for e.g. with large object field and put there GB of data and system break
down. What should I do. Joe must connect to the base because he must select
some data from table but it must be all. I will be very greatfull for any
sugestion.

Mateusz Mazur
POLAND
vincent(at)waw(dot)pdi(dot)net