 <p>Yes, you are doing this correct. Ignore the singleton comment, singletons are a good thing to avoid.</p> <p>Although I do want to make a suggestion:</p> <p>I'm going to assume BD is some kind of database. The power of OOP is the ability to subclass things, and replace objects without changing behaviour.</p> <p>So it <em>may</em> be better to just pass your $bd object in the constructor. Just something to keep in mind. This is called 'dependency injection' or 'inversion of control'.</p>