OK, I think the problem is with a breakdown in communication that you experienced with
LB earlier. I'm going to come right out and say it, I think that you are looking to dump a database off of a website. You should know that this is more then likely illegal in your country and is in fact a felony in the United States. You should find a different hobby if this is what you intend to do.
That being said in the interest of academia, the method you would use to accomplish this would have to be tailored specific to the target. You have to remember that in order for a web server to be useful, it has to except commands that are sent to it from any number of hosts and it needs to respond to those commands in a consistent and meaningful way. Reception of these commands is done by a special process called either a service or a daemon that is hosted on the web server. This is a special process\process pool that is dedicated to dealing with these requests. Everything is done in text, although the actual encoding of that text may vary. How that text is interpreted or interpolated is based on a pre-existing set of rules known as a protocol. Identify the protocol, learn it and then figure out what you can and cannot do with it. There is no magic to any of this, it's all documented. Otherwise nothing would work.
You asked earlier why penetration testers use programmatic approaches to looking for flaws? The answer is that it is faster to figure out things that way then it is to use telnet and type everything in by hand. Here's your freebie OP:
http://nmap.org/ and now I will say it again
DO NOT DO ANYTHING STUPID. DO NOT GET INTO TROUBLE. I am only entertaining you because it was stuff like this that launched my own interest into computer science. I know how interesting this stuff feels and I know how infuriating it can be to hit a dead end or to ask a question and have nobody answer; or worse they answer with some cryptic and esoteric garbage that basically tells you to take a hike.
As for Data Forensics, that field is all about data recovery and reconstruction. Most methods they employ involve having physical access to the hardware in question. This one isn't really my field and I usually defer to people who are better qualified then I am.