Thank Robert and Ron, Could you list an example where I need to use rpm command alone? I used rpm to install stand alone package if that is the case.
This one illustrates the kind of information you rather get with the rpm command (here the installed size):
# List RPMS ordered by size (biggest last) rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n
Useful when you need to make room in an /usr partition for example