Properly pass connection to connstructor PDO - php

Question

I have spent several days reading different tutorials posts etc either info is outdated or appreciated.
I have a database connection class very simple
namespace App\Database;
use PDO;
use PDOException;
/**
* #desc Connection to the database
**/
class Database
{
protected string $dbhost = DATABASE_HOST;
protected string $dbuser = DATABASE_USER;
protected string $dbpass = DATABASE_PASS;
protected string $dbname = DATABASE_NAME;
protected PDO $conn;
public function __construct()
{
// Set DSN
$dsn = 'mysql:host=' . $this->dbhost . ';dbname=' . $this->dbname . ';charset=' . $this->charset;
$options = array(
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
);
// Create PDO instance
try {
$this->conn = new PDO($dsn, $this->dbuser, $this->dbpass, $options);
} catch (PDOException $e) {
echo 'Unable to establish a database connection: ' . $e->getMessage();
exit();
}
}
}
and in my user class I passed it to the constructor
protected Database $conn;
public function __construct()
{
$this->conn = new Database;
}
but when i write a statement like this
$stmt = $this->conn->prepare($sql);
prepare is high lighted saying Method 'prepare' not found in \App\Database\Database
I would prefer not to use static or singleton

Answer 1

Your variable $conn would probably better be named $db:
protected Database $db;
public function __construct()
{
$this->db = new Database;
}
Then, when you understand that the User class has a property called db which in turn has a property called conn, the proper use might make more sense:
$stmt = $this->db->conn->prepare($sql);
However, you've defined $conn as protected, so you can't do that. You could make it public, or make a getter method in Database:
public function getConn(): PDO
{
return $this->conn;
}
And then do:
$stmt = $this->db->getConn()->prepare($sql);
Better, I'd forget all that and instead have Database extend PDO, then just override the constructor to configure with your custom values:
class Database extends PDO
{
public function __construct()
{
$dsn = sprintf(
'mysql:host=%s;dbname=%s;charset=%s',
DATABASE_HOST,
DATABASE_NAME,
DATABASE_CHARSET
);
parent::__construct(
$dsn,
DATABASE_USER,
DATABASE_PASS,
[
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
]
);
}
}
Now you have a PDO-compatible database object that is pre-configured, and you can just use it like a regular PDO object:
class User
{
protected Database $db;
public function __construct(Database $db)
{
$this->db = $db;
}
public function whatever()
{
$this->db->prepare($sql);
// ...
}
}
$db = new Database();
$user = new User($db);
$user->whatever();