Какой вариант лучше для реализации?

Какой вариант лучше для реализации: статическими методами или через объект?

class DataBase
{
    protected $host = "localhost";
    protected $user = "admin";
    protected $pasword = "777";
    protected $db = "blog";
    protected  function conect ()
    {
        $conect = mysqli_connect($this->host, $this->user, $this->pasword, $this->db);
        return $conect;
    }
}

class category extends DataBase           
{  
    public function select ($category)
    {
        $select = "SELECT * FROM article WHERE id = '$category'";
        return $select;
    }
    public function result ($argument)
    {
        $result = mysqli_query($this->conect(), $this->select($argument));
        while ($myrow[] = mysqli_fetch_assoc($result));
        return $myrow;  
    }
}
class SelectAll extends category          
{  
    public function select ($category)
    {
        $select = "SELECT * FROM article LIMIT $category , 5";
        return $select;
    }

}

или же так:

class DataBase
{
    public static $host = "localhost";
    public static $user = "admin";
    public static $pasword = "777";
    public static $db = "blog";
    public static function conect ()
    {
        $conect = mysqli_connect(self::$host, self::$user, self::$pasword, self::$db);
        return $conect;
    }
}
class category extends DataBase           
{  
    public static function select ($category)
    {
        $select = "SELECT * FROM article WHERE id = '$category'";
        return $select;
    }
public static function result ($argument)
    {
        $result = mysqli_query(self::conect(), static::select($argument));
        while ($myrow[] = mysqli_fetch_assoc($result));
        return $myrow;  
    }
}

 class SelectAll extends category         
 {  
    public static function select ($category)
    {
        $select = "SELECT * FROM article LIMIT $category , 5";
        return $select;
    }
}