PHP: Assigning new PDO as object-attribute

Question

I am trying to build a PDO connection to my MySQL database. This PDO is also being inherited by the child-classes of this class, where connection-specific functions are called from. When I call these connection-specific functions from the child-classes, I get an error.

So within the parent class, I have the following code:

...
protected $pdo;

public function __constructor() { //Check if public
    try {
        $pdo_local = new PDO(C_DB_PDODRIVER . ":host=" . C_DB_HOST . ";dbname=" . C_DB_DATABASE, C_DB_USERNAME, C_DB_PASSWORD);
        $this->pdo = $pdo_local;
    } catch (\PDOException $e) {
        header("Location: error.html");
        exit;
    }
}
...

However, whenever I try to call the prepare statement of $this->pdo, I get a "Call to a member function prepare()" fatal error.

$query = "SELECT * FROM stacks WHERE id = :id LIMIT 1";

$stm = $this->pdo->prepare($query);

$para = array("id"=>$id); //where $id is the input parameter of the function
$stm->execute($para);
$result = $stm->fetch();

I have read that the PDO data-object is a null object, but I don't understand why? shouldn't $this->pdo = $pdo_local change that?

I am quite new to StackOverflow, so sorry if this question has flaws. Also, If you see any possible improvements in my code, please tell me!

Answer 1

Proper function name for constructor is __construct.