为什么我的所有数据都成为字符串，即使它最初是我的数据库中的整数？

Question

我是PHP开发的初学者，我有＆＃39; User＆＃39;我的数据库中的表格如下，因为我们可以看到＆＃39; id＆＃39;和＆＃39; emailConfirmed＆＃39;实际上是整数。

从数据库获取用户数据，我使用下面的PHP代码，这是我使用的简化代码：

class access {


    public $host = null;
    public $username = null;
    public $password = null;
    public $dbname = null;
    public $conn = null;
    public $result = null;

    function __construct($xhost,$xusername,$xpassword,$xdbname) {
        $this->host = $xhost;
        $this->username = $xusername;
        $this->password = $xpassword;
        $this->dbname = $xdbname;
    }


    function getUserData ($username) {

        $returnArray = [];

        $query = "SELECT * FROM users WHERE username = '$username'";
        $result = $this -> conn -> query($query);

        if ($result != null && (mysqli_num_rows($result)>0)) {

            $row = $result->fetch_array(MYSQLI_ASSOC);

            if (!empty($row)) {
                $returnArray = $row;
            }

        }

        return $returnArray;


    }
}



require_once("security/access.php");


$username = htmlentities(strtolower(stripcslashes($_REQUEST["username"])));
$password = htmlentities(strtolower(stripcslashes($_REQUEST["password"])));


if (empty($username) || empty($password)) {

    $returnArray = [
        "status" => "400",
        "message" => "missing required information"
    ];

    echo json_encode($returnArray);
    return;

}

$file = parse_ini_file("../../../twitter.ini");
$dbhost = trim($file["host"]); 
$dbusername = trim($file["username"]);
$dbpassword = trim($file["password"]);
$dbname = trim($file["dbname"]);


$access = new access($dbhost,$dbusername,$dbpassword,$dbname);
$access->connect();

$user = $access -> getUserData($username);


if (empty($user)) {
    $returnArray = [
        "status" => "403",
        "message" => "User is not found"
    ];

    echo json_encode($returnArray);
    return;
} else {

    $passwordDB = $user["password"];


    if (password_verify($password,$passwordDB)) {

        //login successfully

        $returnArray = [

        "status" => "200",
        "message" => "Login Success!",
        "id" => $user["id"],
        "username" => $user["username"],
        "email" => $user["email"],
        "avatar" => $user["avatar"],
        "fullname" => $user["fullname"],
        "emailConfirmed" => $user["emailConfirmed"]
    ];

    } else {
        $returnArray = [
        "status" => "403",
        "message" => "Password didn't match"
    ];
    }

}

$access ->disconnect();

echo json_encode($returnArray); 

我在我的iOS应用程序中使用该代码，并在从服务器获取后直接将用户数据保存到本地数据库（数据持久性用户默认值），如下所示，因为我们可以看到＆＃39; id＆＃39;和＆＃39; emailConfirmed＆＃39;现在变成了字符串，而不是整数。

我不认为我在客户端代码中进行了数据类型操作，我在PHP代码中出错了所以我的Integer现在变成了String吗？还是在客户端代码错误？这是我在swift中的代码，用于发出请求并使用用户默认值在本地保存数据。

// connect to MySQL database
            let url = URL(string: "http://localhost/twitter/login.php")

            var request = URLRequest(url: url!)
            request.httpMethod = "POST"

            let body = "username=\(usernameTextField.text!)&password=\(passwordTextField.text!)"
            request.httpBody = body.data(using: .utf8)

            let session = URLSession.shared
            let task = session.dataTask(with: request, completionHandler: { (data, response, error) in

                if error == nil {

                    DispatchQueue.main.async {

                        self.activityIndicator.startAnimating()

                        do {
                            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary

                            guard let parsedJSON = json else {
                                print ("error while parsing JSON")
                                return
                            }


                            let status = parsedJSON["status"] as! String
                            let message = parsedJSON["message"] as! String


                            if status == "403" {
                                self.activityIndicator.stopAnimating()
                                self.showAlert(alertTitle: "ooppss!", alertMessage: message, actionTitle: "OK")
                                return
                            } else {


                                let confirmedUser = parsedJSON["emailConfirmed"] as! String

                                if confirmedUser == "1" {
                                   UserDefaults.standard.set(parsedJSON, forKey: "parsedJSON")
                                    userInfo = UserDefaults.standard.object(forKey: "parsedJSON") as? NSDictionary

                                    self.activityIndicator.stopAnimating()
                                    self.performSegue(withIdentifier: "goToHomePage", sender: self)
                                } else {
                                    self.activityIndicator.stopAnimating()
                                    self.showAlert(alertTitle: "sorry", alertMessage: "please complete your registration process first, please check your email", actionTitle: "OK")
                                }



                                print(parsedJSON)


                            }





                        } catch {
                            print("\n\n===========Error===========")
                            print("Error Code: \(error._code)")
                            print("Error Messsage: \(error.localizedDescription)")
                            if let data = data, let str = String(data: data, encoding: String.Encoding.utf8){
                                print("Server Error: " + str)
                            }
                            debugPrint(error)
                            print("===========================\n\n")

                        }
                    }


                } else {
                    // get main queue to communicate back to user
                    DispatchQueue.main.async(execute: {
                        let message = error!.localizedDescription
                        self.showAlert(alertTitle: "oppps", alertMessage: message, actionTitle: "OK")
                    })
                }




            })

            task.resume()
        }

    }

所以这里出了什么问题？