... abstract (db connection::execute, db connection:: prepare)in /Users/george /Advanced PHP/ examples/chapter-2/14 .php on line 3 PHP does not support multiple inheritance.That is, a class cannot directly ... necessary because PHP cleans up resources atthe end of a request. For long-running scripts or scripts that open a large number offiles, aggressive resource cleanup is important.In PHP4 , objects ... abandoned in PHP5 .In PHP5 , when you create an object, you are returned a handle to that object, whichis similar in concept to a reference in C++.When you execute the preceding codeunder PHP5 , you...