PHP DateTime class Namespace
DateTime is in the global namespace, and as "class names always resolve to the current namespace name" you have to use \DateTime.
Or import the package using:
use \Datetime;
Better solution for using classes in global namespaces is "use" keyword instead of "\" before class.
namespace SDCU\GeneralBundle\Entity;
use \DateTime;
class Country
{
public function __construct(){
$this->insertedAt = new DateTime();
}
}