How to recover from corrupt rpm database on RHEL/CentOS/Fedora

First and foremost thing take a backup of the existing rpm database( yes the corrupted one...you never know...).This is located in /var/lib/rpm ..depend on your distribution.

Now go to that dir(/var/lib) and take a backup of entire rpm dir ..like this:

tar -cvzf rpm-date.tar.gz rpm

And finally start rebuilding the rpm database like this:

cd /var/lib/rpm

rm -f __db* # delete it if present