php - 用户评论未使用 PDO 输入数据库

Question

我正在尝试创建一个页面以允许用户对图书发表评论。我正在检查字段是否为空，用户名是否存在于用户表中，图书 ID 是否存在于图书表中。如果所有这些都通过了，那么我想将评论输入评论表。

目前，当我填写表单并提交时，我没有得到任何输出，没有错误，只有一个空白屏幕。

代码如下:

require_once __DIR__.'/config.php';
session_start();
$dbh = new PDO('mysql:host=' . DB_HOST . ';dbname=' . DB_USERNAME, DB_USERNAME, DB_PASSWORD);

$book = $_POST["book_id"];
$username = $_POST["user"];
$review = $_POST["review"];
$rating = $_POST["rating"];

if (empty($book) || empty($username) || empty($review) || empty($rating) ) {
    $error = "Complete all fields";     
}

if ($rating > 5 || $rating < 0) {
    $error =  "Please enter a rating between 1 and 5";
}

if (!isset($error)){
    //no error
    $stmt = $dbh->prepare("SELECT username FROM users WHERE username = :user");
    $stmt->bindParam(':user', $username);
    $stmt->execute();
} else {
    $error = "user does not exsist";
}

if (!isset($error)){
    //no error
    $stmt = $dbh->prepare("SELECT b_id FROM users WHERE b_id = :book_id");
    $stmt->bindParam(':book_id', $book);
    $stmt->execute();
} else {
    $error = "Book does not exsist, please enter another ID";
}       

if (!isset($error)) {
    $sql = 'INSERT INTO reviews (book_id ,username, review, rating) VALUES (:book_id,:user,:review,:rating)';    
    $query = $dbh->prepare($sql);

    $query->execute(array(
        ':book_id' => $book,
        ':user' => $username,
        ':review' => $review,
        ':rating' => $rating    
    ));
} else {
    echo "error occured: ".$error;
    exit();
}

我想进行检查并将信息输入数据库，谁能告诉我如何操作？

Answer 1

根据上次查询的错误输出，reviews 表似乎没有 username 字段。这也是合乎逻辑的 - 我认为它应该类似于 user_id(作为 PK 关系)。

Query 1 Error output: Array ( [0] => 00000 [1] => [2] => )
Query 2 Error output:  Array ( [0] => 00000 [1] => [2] => )
Query 3 Error output:  Array ( [0] => 42S22 [1] => 1054 [2] => Unknown column 'username' in 'field list' )

查询:

$sql = 'INSERT INTO reviews (book_id ,username, review, rating) VALUES (:book_id,:user,:review,:rating)';    
    $query = $dbh->prepare($sql);

提到的错误是:

Unknown column 'username' in 'field list'