MySQL.. way over my head.

Okay, here's the main problem; I can find and install PHP modules, no problem. I can even edit them enough to personalize them, given the time to do so, but when it comes to the MySQL databases I have no clue *whatsoever* of what I am looking at.

Now, the specific issue this is causing is that my users have to both signup for, and login to, a seperate service on each page rather than signing in one time and being done with it, and I hate that.

I'm bright enough to realize that the obvious solution is to use a single database for the entire website, but I don't even know how to begin with that. I've looked at some of the variables in each database and have pondered the possible solutions and all I can come up with is to build one giant database which would include all of the variables; and then alter the PHP files to make them refer to that database.

Two things there, first, is it even possible to do this, and also could there be conflicting information? How would I go about checking for that? Second, if so, is it a good idea? I've seen hefty databases take hours to search; this certainly wouldn't even measure up to that, but I definatly don't want my users to have to sit for ten minutes loging in.

Now, annother idea I had was to keep the databases seperate and just have a single login database that also logged each user into the other features. Is that possible? Would this mean learning more PHP ( which I'm completely up for. )

I can extract the databases from the site if anybody wants to take a look at them. Obviously I'll leave the usernames and passwords out. Any help, or even if you can't help directly but could point me at a place to learn, would be greatly appreciated.

Thanks for reading.