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
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