PHP calling class from another class

Question

I want to call a PHP class in another class and get the following error:

Fatal error: Call to a member function quote() on a non-object

Class 1:

class logmein {

    //Connect DB
    function dbconnect(){
        require_once('class.MySQL.php');
        $db = new Db();    

    }

    //login function
    function login($username, $password){

        //conect to DB
        $this->dbconnect(); 

        // Quote and escape form submitted values
        $name = $db -> quote($username);                    //throwing error
        $email = $db -> quote($password);                   //throwing error

    }
}

Class 2:

class DB {

    public function quote($value) {
        $connection = $this -> connect();
        return "'" . $connection -> real_escape_string($value) . "'";
    }
}

I call it:

$log = new logmein();
$log->login('James Bond', '007');

What I have to do to call them into each other? Or is there a other way to do that. Thanks a lot for help!

possible duplicate of [What is a class in PHP?](http://stackoverflow.com/questions/2206387/what-is-a-class-in-php) — Ryan, Jan 14 '15 at 21:25
looks to me that $db is not visible outside of logmein::dbconnect — Jasen, Jan 15 '15 at 07:35

score 1 · Accepted Answer · answered Jan 14 '15 at 21:17

The $db object falls out of scope from dbconnect() to login(). Set it as a class property instead so you can access it anywhere in your class:

class logmein {

    protected $db; // property available to this class and child classes

    //Connect DB
    function dbconnect(){
        require_once('class.MySQL.php');
        $this->db = new Db(); // say "$this" to refer to it

    }

    //login function
    function login($username, $password){

        //conect to DB
        $this->dbconnect(); 

        // Quote and escape form submitted values
        $name = $this->db->quote($username); // works now
        $email = $this->db->quote($password); // works now

    }
}

score 0 · Answer 2 · answered Jan 14 '15 at 21:21

You need to be sure that the DB is accessible across your class functions, so it needs to be stored in a class property.

class logmein {
    private $db; //store the database object

    //Connect DB
    function dbconnect(){
        require_once('class.MySQL.php');
        $this->db = new Db();    

    }

    //login function
    function login($username, $password){

        //conect to DB
        $this->dbconnect(); 

        // Quote and escape form submitted values
        $name = $this->db->quote($username);
        $email = $this->db->quote($password);

    }
}

That being said, this setup is tightly coupling your database with the login. Consider looking into 'dependency injection' and other ways to keep your code components separate.

PHP calling class from another class

2 Answers2