php - 如何在Mysql中将对象属性设置为null

Question

我正在将对象列表上传到 MySQL。某些对象不包含相同数量的变量。例如

Objectt1 {
property1
property 2
}

Objectt2 {
property1
property2
property3
}

Objectt3 {
property1
}

我的问题是mysql中的Object3被赋予了property2和property3而不是NULL。该值是从 Object2 中获取的。如何使对象 3 的 property2 和 property3 为空？ php代码如下:(我想我明白为什么这样做，因为该变量已经在之前的循环运行中设置了。但我不知道如何修复它。)

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);


if($_SERVER["REQUEST_METHOD"] == "POST") {
    require 'connection.php';
    uploadstart();
}

function uploadstart() {
    global $connect; 

    $json = $_POST["objectlist"];

    //Remove Slashes
    if (get_magic_quotes_gpc()){
        $json = stripslashes($json);
    }

    $createworkoutquery = $connect->prepare("INSERT INTO objectTable 
                                                (id, prop1, prop2, prop3) 
                                         VALUES (?, ?, ?, ?)");

    $createworkoutquery->bind_param("ssss", $ID, $prop1, $prop2, $prop3) ;
    //convert json object to php associative array
    $data = json_decode($json, true);

    //Util arrays to create response JSON
    $a=array();
    $b=array();

    // loop through the array
    foreach ($data as $row) {
        // get the list details
        $ID = $row["id"];    
        $prop1 = $row["prop1"];

        if (isset($row["prpop2"])) {
            $prop2 = $row["prop2"];
        }

        if (isset($row["prop3"])) {
            $prop3 = $row["prop3"];
        }


        // execute insert query
        $result = $createworkoutquery->execute();

        //if insert successful.. plug yes and woid else plug no
        if($result){
            $b["id"] = $ID;
            $b["status"] = 'yes';
            array_push($a,$b);
        } else {
            $b["id"] = $ID;
            $b["status"] = 'no';
            array_push($a,$b);
        }
    }

    echo json_encode($a);

    //close connection
    mysqli_close($connect);

}
?>

Answer 1

在每次迭代时将 null 分配给缺失的属性，以便以前的值不会绑定(bind)到查询:

foreach($data as $row){
    $ID = $row['id'];
    $prop1 = isset($row['prop1'])? $row['prop1']: null;
    $prop2 = isset($row['prop2'])? $row['prop2']: null;
    $prop3 = isset($row['prop3'])? $row['prop3']: null;

    $result = $createworkoutquery->execute();
    ...
}