PHP准备好的语句将数据插入到除一个表以外的所有表中（MySQL）

Question

我正在使用收件箱系统。在前端，它使用jQuery和Ajax，因此不会刷新页面。我已经处理了这个部分。在后端，有3个表格（现在）可以插入数据。

这里是关系结构的基本概要：

conversations: 
conversation_id int(11) primary key 
conversation_subject varchar(128) 

conversations_members: 
conversation_id int(11) 
user_id int(11) 
conversation_last_view int(10) 
conversation_deleted int(1) 

conversations_messages: 
message_id int(11) primary key 
conversation_id int(11) 
user_id int(11) 
message_date timestamp 
message_text text 

因为SENDER_ID始终为0有一个额外的问题，但必须是另一个问题，因为这是题外话。 问题在于conversations_members表。其他所有内容都会输入到对话和conversations_messages表格中。这里是PHP。问题是在底部的最后一个SQL查询：

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

include('../inc/connect.php'); 
if (!isset($_SESSION['username'])) { 
    session_start(); 
} 
$recipient_username = ""; 
$sender_id = ""; 
$a = 0; 
$b = 0; 
if(isset($_POST['subject'], $_POST['msg_body']) &&  !empty($_POST['subject']) && !empty($_POST['msg_body'])) { 

//get ID of sender 
$sender_id_query = "SELECT id FROM `users` WHERE username = ?"; 
$stmt = $connection->prepare($sender_id_query); 
$stmt->bind_param('s', $_SESSION['username']); 
$stmt->execute(); 
$result = mysqli_query($connection, $sender_id_query); 
if($result) { 
    while($row = mysqli_fetch_assoc($result)) { 
     //$row['id'] = $sender_id;   //neither of these work 
     $sender_id = $connection->insert_id; //Always zero 
    } 
} 
$stmt->close(); 

//get username of recipient 
$recipient_name_query = "SELECT * FROM `users`"; 
$result = mysqli_query($connection, $recipient_name_query); 
if($result) { 
    while($row = mysqli_fetch_assoc($result)) { 
     $row['username'] = $recipient_username; 
    } 
} 
//define post variables 
$msg_subject = $_POST['subject']; 
$msg_body = $_POST['msg_body']; 
$subject = $connection->real_escape_string(htmlentities($msg_subject)); 
$body = $connection->real_escape_string(htmlentities($msg_body)); 
$conversation_id = mysqli_insert_id($connection); 


//GET RECIPIENT ID 
$sql = "SELECT id FROM `users` WHERE username=?"; 
$stmt = $connection->prepare($sql); 
$stmt->bind_param('s', $recipient_username); 
$result = mysqli_query($connection, $sql); 
if ($result) { 
    while ($row = mysqli_fetch_assoc($result)) { 
     $recipient_id = $row['id']; 
    } 
} 
$stmt->close(); 

//INSERT SUBJECT INTO CONVERSATIONS TABLE 
$stmt = $connection->prepare("INSERT INTO `conversations` (conversation_subject) VALUES(?)"); 
$stmt->bind_param('s', $subject); 
$stmt->execute(); 
$stmt->close(); 


//INSERT THE IDs AND TIMESTAMPS INTO MESSAGES TABLE 
$stmt = $connection->prepare("INSERT INTO `conversations_messages` (conversation_id, user_id, message_date, message_text) 
           VALUES(?, ?, NOW(), ?)"); 
$stmt->bind_param('iis', $conversation_id, $sender_id, $body); 
$stmt->execute(); 
$stmt->close(); 

/* 
THE FOLLOWING DATA DOES NOT GET INSERTED..... 
*/ 
//INSERT IDs, LAST_VIEWED, AND DELETED INTO MEMBERS TABLE 
$stmt = $connection->prepare("INSERT INTO `conversations_members` (conversation_id, user_id, conversation_last_view, conversation_deleted) 
           VALUES (?, ?, ?, ?)"); 
$stmt->bind_param('iiii', $conversation_id, $recipient_id, $a, $b); 
$stmt->execute(); 
$stmt->close(); 
} 

我没有得到任何错误，我没有看到任何错别字。我哪里做错了？

Answer 1

感谢其他错误检查的建议，它让我发现发生了什么。我完全删除了while循环，并且给每个$ stmt变量赋予了自己的名字，因为我在删除while循环后发现了另一个错误。第一个语句之后的每个语句都返回一个FALSE值，因为前一个语句没有关闭。此代码有效。我没有收到任何错误，并根据需要将所有内容插入到数据库中。

$recipient_username = $_GET['username']; 
$username = $_SESSION['username']; 
$a = 0; 
$b = 0; 


//get ID of sender 
$sender_id_query = "SELECT id FROM `users` WHERE username = ?"; 
$stmt = $connection->prepare($sender_id_query); 
$stmt->bind_param('s', $username); 
$stmt->execute(); 
$stmt->bind_result($sender_id); 
$val = $stmt->fetch()[$sender_id]; 
$stmt->close(); 

//define post variables 
$msg_subject = $_POST['subject']; 
$msg_body = $_POST['msg_body']; 
$subject = $connection->real_escape_string(htmlentities($msg_subject)); 
$body = $connection->real_escape_string(htmlentities($msg_body)); 
$conversation_id = mysqli_insert_id($connection); 

//GET RECIPIENT ID 
$recipient_id_query = "SELECT id FROM `users` WHERE username=?"; 
$stmt2 = $connection->prepare($recipient_id_query); 
$stmt2->bind_param('s', $recipient_username); 
$stmt2->execute(); 
$stmt2->bind_result($recipient_id); 
$val_2 = $stmt2->fetch()[$recipient_id]; 
$stmt2->close(); 

//INSERT SUBJECT INTO CONVERSATIONS TABLE 
$stmt3 = $connection->prepare("INSERT INTO `conversations` (conversation_subject) VALUES(?)"); 
$stmt3->bind_param('s', $subject); 
$stmt3->execute(); 
$stmt3->close(); 

//INSERT THE IDs AND TIMESTAMPS INTO MESSAGES TABLE 
$stmt4 = $connection->prepare("INSERT INTO `conversations_messages` (conversation_id, user_id, message_date, message_text) 
           VALUES(?, ?, NOW(), ?)"); 
$stmt4->bind_param('iis', $conversation_id, $sender_id, $body); 
$stmt4->execute(); 
$stmt4->close(); 


//INSERT IDs, LAST_VIEWED, AND DELETED INTO MEMBERS TABLE 
$stmt5 = $connection->prepare("INSERT INTO `conversations_members` (conversation_id, user_id, conversation_last_view, conversation_deleted) 
           VALUES (?, ?, ?, ?)"); 
$q = $stmt5->bind_param('iiii', $conversation_id, $recipient_id, $a, $b); 
$stmt5->execute(); 
$stmt5->close();