Difference between rpm -ivh and rpm -Uvh
Check out documentation (man page) of rpm.
i - install (This installs a new package)
v - verbose (using or expressed in more words than are needed)
h - hash (Print 50 hash marks as the package archive is unpacked)
U - upgrade (This upgrades or installs the package currently installed to a newer version. This is the same as install, except all other version(s) of the package are removed after the new package is installed)