Introduction to PHP for Web Developers
The more things are tangled up and depend on each other, the harder they are to work with. If you want to change your HTML, it’s a bit hard without your SQL stuff getting in the way. If you’re trying to fix something in the way the data is structured, you’ve got HTML in up in your grill. Bear in mind this is a simple example. An actual app would be much more complex and that gets exponentially more tangly.