ERROR in PDO : Call to a member function prepare() on null

Question

I have a problem with prepare function ==> Call to a member function prepare() on null i have tow pages classo.php and index.php

class

Answer 1

There are 2 big issues in your code:

1. Variable visibility
2. Static call

In detail:

1. In oop you should forget about global variables. They are against the principle of encapsulation. Moreover, you do not even have any global variable in your code, so global $db; line is meaningless. Declare a private $db variable on class level (property) initialise it in the connection() method and access it in the insert method.

2. You are calling the connection method as classo::connection();. However, you would need to declare connection method as static. Either declare your connection method as static (but then change $db into static as well), or call it as a regular method using $this.