So if NcFTPd doesn do MySQL/mSQL/Oracle/etc, then what is this NcFTPd Password Database you e talking about?
These are database files which are created and maintained by the ncftpd_passwd utility program that comes with the NcFTPd package. These databases are much faster than scanning the /etc/passwd file and are suited thousands of users. The database files are also used to store individual quota and bandwidth information, so if you want those features you have to use a password database.