Update Databases from Webserver

[FreeBSD Mail Lists]

Hello,

I would like to see how other people are updating backend databases (postgresql on FreeBSD, internal network) from a webserver (apache,php on FreeBSD, dmz network) through a firewall.  Pretty much what I am trying to learn is how to take private information (credit card numbers, etc.) and write it to a backend database without leaving any huge holes for hacking.  Should this be done or am I barking up the wrong tree, should there be an intermediary step?  I have been trying to find information books/web that gives a real nuts and bolts way of trying to do this stuff and am not having a lot of luck.  Any pointers books or sites would be appreciated.

Thanks for your time.
Troy