How to properly set up a PDO connection using anonymous function and closures

Question

With the help of the answer on a post on similar topic Answer by "teresko" I have managed to understand the factory design method to establish connection to my database. But I am unable to implement the logic in my code as I am receiving this error:

Fatal error: Class 'conn' not found in C:\somewhere\db2.php on line 42

Here is my db file:

$provider = function() {
    $db_user="root"; // db user
    $db_password="";// db password (mention your db password here)
    $db_database="cl";// database name
    $db_host="localhost"; // db server

    $instance = new PDO("mysql:host=$db_host;dbname=$db_database", $db_user, $db_password);
    $instance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $instance->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
    return $instance;
};

$factory = new StructureFactory( $provider );
$conn = $factory->create('conn');

class StructureFactory {
   // protected $provider = null;
   protected $connection = null;

   public function __construct( callable $provider ) {
       $this->provider = $provider;
   }

   public function create($name) {
       if ( $this->connection == null ) {
           $this->connection = call_user_func( $this->provider );
       }
       return new $name($this->connection );
   }
}

Since I am a new user, I am unable to request this question as a comment on the original answer. Can you guys help me work out where I'm going wrong please? As the original question says, "I would really like to know how to properly connect to a MySQL database using PHP and PDO and make it easy access-able.I'm eager to learn..."

Answer 1

Given you are a new user, just make it simple PDO instance.

$db_user="root"; // db user
$db_password="";// db password (mention your db password here)
$db_database="cl";// database name
$db_host="localhost"; // db server
$db_charset="utf8";

$conn = new PDO("mysql:host=$db_host;dbname=$db_database;charset=$db_charset", $db_user, $db_password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);