Fatal error: Call to a member function prepare() on null
In ---- model:
Add use Jenssegers\Mongodb\Eloquent\Model as Eloquent;
Change the class ----- extends Model
to class ----- extends Eloquent
It looks like your $pdo
variable is not initialized.
I can't see in the code you've uploaded where you are initializing it.
Make sure you create a new PDO object in the global scope
before calling the class methods. (You should declare it in the global scope because of how you implemented the methods inside the Category class).
$pdo = new PDO('mysql:host=localhost;dbname=test', $user, $pass);