mysql - Php mysqli database connection fail? -

goodday,

i strange error.

this code:

<?php $con=mysqli_connect("localhost","root","","testdatabase");  class database{     public function select($tablename){         $result = mysqli_query($con,"select * ".$tablename);            }        }  $database = new database(); ?> 

the error message $con undefined variable. define $con on line number 2?

when var_dump con says null.

what doing wrong?

if want access $con var in method or function, have globalize inside code :

public function select($tablename){     global $con;     $result = mysqli_query($con,"select * ".$tablename);        } 

but shouldn't that, globals evil !

this how code should :

<?php class database{     protected $con;      public function __construct($host, $user, $password, $dbname){         $this->con = mysqli_connect($host, $user, $password, $dbname);     }      public function select($tablename){         $result = mysqli_query($this->con,"select * ".$tablename);            }        }  $database = new database("localhost", "root", "", "testdatabase"); ?>