oop - PHP inheritance - when to use parent? -

this question has answer here:

• access parent's overridden method parent's context in php 4 answers
• proper way load base class + extended class in php 2 answers

in particular example, have parent class , children classes inheriting parent.

in parent class, have public variable called $abc , method called abc():

public $hello = 'hi';  class abc {   function abc() {     ...   } } 

inherited child class:

class def extends abc {   function def() {     parent::abc();     echo $this->hello;   } } 

my question is, why use parent:: access method parent class, use $this-> access variable, instead of parent:: well? sticking $this-> know theory behind that.

class def extends abc {   function abc() {     return parent::abc(); // here use parent!   } } 

you use parent:: call method belong parent might/was overridden child.