This module lets you stack handlers so that the next one will handle
or "filter" the output of previous one.

From README:

    Don't you hate keeping track of database passwords and such
    throughout your scripts? How about the problem of changing those
    passwords on a mass scale? This module is one possible solution.
    When you go to build this module it will ask you to create
    virtual users. For each user you need to specify the database
    module to use, the database connect string, the username and the
    password. You will be prompted to give a name to this virtual
    user. You can add as many as you like.

WWW: http://search.cpan.org/dist/DBIx-Password/