How to set up and inject multiple PDO database connections in slim 4?

Question

I could make an instance of PDO and inject it successfully. I defined the PDO::class directly and injected it in the constructor with __const

Answer 1

You have multiple options:

1. Extending PDO
2. Autowired objects

1. Extending PDO

use PDO;

class PDO2 extends PDO
{
    // must be empty
}

The container definition:

use PDO2;

// ...

return [
    PDO::class => function (ContainerInterface $container) {
        return new PDO(...);
    },

    PDO2::class => function (ContainerInterface $container) {
        return new PDO2(...);
    },
];

Usage

use PDO;
use PDO2;

class MyRepository
{
    private $pdo;

    private $pdo2;
    
    public function __construct(PDO $pdo, PDO2 $pdo2)
    {
        $this->pdo = $pdo;
        $this->pdo2 = $pdo2;
    }
}

2. Autowired objects

See Matthieu Napoli's answer: https://stackoverflow.com/a/57758106/1461181