Please refer the following steps:
[root@server1]# cd /var/lib/rpm/
[root@server1 rpm]# ll | grep db
-rw-r–r– 1 root root 2476 Sep 8 15:43 __db.001
-rw-r–r– 1 root root 13112 Sep 8 15:43 __db.002
-rw-r–r– 1 root root 45560 Sep 8 15:43 __db.003
[root@server 1rpm]# rm __db*
rm: remove regular file `__db.001′? y
rm: remove regular file `__db.002′? y
rm: remove regular file `__db.003′? y
[root@server rpm]# rpm –rebuilddb
This should build your RPM database again.