So, I want to know how to do that, and I pretty
You do need to update and retrieve through JSON ? If this is the case, you'll probably have to code some Web Service and such, (it won't necessarily be in PHP, could be Java, C#, whatever)
Look at this thread, it seem there is no way you can access MySql server directly from android, so indeed, you may need some Web development implement the JSON/XML middle layer to connect with android.
Thread @ StackOverFlow Android + MySQL using com.mysql.jdbc.Driver