The Scope resolution operator (::) allows access to static, constant properties or methods of a class. When referring to a class outside the class definition, we must use class name. 

Syntax for scope resolution operator

<?php
    class className
    {
        const CONS = "value here...";
    }
    $var = 'className';
    echo $var::CONS; // access the const under class
?>

When an extending class overrides a method, it does not necessarily call its parent class. It is up to the extended class whether to call the parent class or not. The example below refers to it:

Example with extending class overriding a method

 

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