I have a singleton db connection which I get with:

$dbConnect = myDatabase::getInstance();

which is easy enough. My question is what is the least rhetorical and legitimate way of using this connection in functions and classes? It seems silly to have to declare the variable global, pass it into every single function, and/or recreate this variable within every function. Is there another answer for this?

Obviously I'm a noob and I can work my way around this problem 10 different ways, none of which is really attractive to me. It would be a lot easier if I could have that $dbConnect variable accessible in any function without needing to declare it global or pass it in. I do know I can add the variable to the $_SERVER array...is there something wrong with doing this? It seems somewhat inappropriate to me.

Another quick question: Is it bad practice to do this:

$result = myDatabase::getInstance()->query($query);

from directly within a function?