PHP calling a method from outside another class - php

Question

Not sure of OOP syntax to do this...
I'd like to have aclass that calls the mysqli object
class Voovid_DB {
private $host = 'localhost';
private $user = 'blahblah';
private $password = 'blahblah';
private $name = 'blahblah';
public function __contstuct(){
$dbh= new mysqli( $this->host, $this->user, $this->password, $this->name );
return $dbh;
}
//get and set methods for host, user etc... go here
}
now I'd like to access all the mysqli methods like so
$dbconnect = new Voovid_DB();
if ( $result = $dbconnect->query( "SELECT first_name, last_name FROM members WHERE member_id=9" ) ) {
while ( $row = $result->fetch_assoc() ) {
$first_name = ucfirst( $row['first_name'] );
$last_name = ucfirst( $row['last_name'] );
}
} else {
$errors = $dbconnect->error;
}
i'm new to PHP OOP and not sure how to get to the mysqli methods inside the Voovid_DB class

Answer 1

You have to either extend the MySQLi class, or build a proxy around it.
The easiest is probably to extend it:
class Voovid_DB extends MySQLi {
private $host = 'localhost';
private $user = 'blahblah';
private $password = 'blahblah';
private $name = 'blahblah';
public function __construct(){
// call parent (MySQLi) constructor
parent::__construct( $this->host, $this->user, $this->password, $this->name );
}
// no need for other methods, they already are there
}
Notice the extends MySQLi.
Then your second code snipet should work.
Or, build a proxy:
class Voovid_DB {
private $host = 'localhost';
private $user = 'blahblah';
private $password = 'blahblah';
private $name = 'blahblah';
private $dbh;
public function __construct(){
$this->dbh = new MySQLi($this->host, $this->user, $this->password, $this->name);
}
// this will proxy any calls to this class to MySQLi
public function __call($name, $args) {
return call_user_func_array(array($this->dbh,$name), $args);
}
}

Answer 2

You could define a __call method:
public function __call($method, $arguments) {
return call_user_func_array(array($this->dbh, $method), $arguments);
}
__call is invoked if an undefined or inivisible method is called.

Answer 3

you code is correct.
the only thing you have to do is to make sure that you define your functions in Voovid_DB as public.
private or protected methods cannot be accessed from other classes
store your mysqli object in a public field in your class then you can access it like this:
$dbconnect->mysqlField->query

Answer 4

Constructors aren't supposed to return anything. When you say $dbconnect = new Voovid_DB(); you would normally be trying to create a Voovid_DB object, but it looks like you're using it to try an make a mysqli object. Don't make this the constructor and call the function after you create the voovid_db object.
$obj = new voovid_DB();
$dbConnect = $obj->createMysqli();