Would singleton be a good design pattern for a microblogging site?

Question

I have not used any OO in the past in projects, as I kept it simpler (in fact using archaic mysql_query calls and my own filtering), so I wanted to start a new project, lear

Answer 1

As said before, the singleton doesn't help you with your blog application much. Just create a single database instance and use it.

Sidenode, what you see in PHP are often "fake singletons". If implemented as plain class, it usually involves using a ::getInstance() method which implements the singleton workaround. The existence of the class however allows to instantiate multiple items (new Singleton() && new Singleton()). Therefore I'd recommend a procedural singleton, which doesn't have this problem and is also much nicer on the eyes:

 function db() {
     static $db;
     if (!isset($db)) {
          $db = new PDO("sqlite:memory");
     }
     return $db;
 }

This way you can use db()->query("SELECT * FROM blog") and avoid to always import a global $db var.