note 107849 added to language.oop5.interfaces

I think good OOP design will actually require both what dlovell2001 and anon said. In the examples below, if Database is only an abstract class, you will have limitations. What if one day you have a special Database object that is so different for some specific needs, that it should NOT inherit from the Database abstract class? You would be stuck. In my opinion, the best thing to do would be to have a Database abstract class that implements a DatabaseInterface interface. When working on a Database object, you would first make sure it implements the DatabaseInterface object (dlovell2001, this is something very important that's missing in your example). You can still use any object inheriting the Database class (because this class implements the DatabaseInterface interface) but you are NOT limited to using an object inheriting from Database. Any object implementing the DatabaseInterface will do. This way, you are not limited to a specific type. Interfaces are a good way to have a 'contract' with the component using a certain object, without being limited to using a specific type for that object. Also remember to use the 'instanceof' or similar when working on such object. One goal of interfaces is to actually enforce the signature of an object before actually working with it. ---- Server IP: 69.147.83.197 Probable Submitter: 69.70.27.42 ---- Manual Page -- http://www.php.net/manual/en/language.oop5.interfaces.php Edit -- https://master.php.net/note/edit/107849 Del: integrated -- https://master.php.net/note/delete/107849/integrated Del: useless -- https://master.php.net/note/delete/107849/useless Del: bad code -- https://master.php.net/note/delete/107849/bad+code Del: spam -- https://master.php.net/note/delete/107849/spam Del: non-english -- https://master.php.net/note/delete/107849/non-english Del: in docs -- https://master.php.net/note/delete/107849/in+docs Del: other reasons-- https://master.php.net/note/delete/107849 Reject -- https://master.php.net/note/reject/107849 Search -- https://master.php.net/manage/user-notes.php