无法生成和插入quiz_id和question_id

Question

我有一个简单的测验程序的以下代码，由于某种原因，它无法生成（和存储到数据库中）测验ID和问题ID，这意味着答案没有任何参考。

管理面板中的代码是：（我认为错误在这里，但不确定）

//inserting the questions into the database
 //checking if the required data has been filled
    if(isset($_POST['desc'])){
        if(!isset($_POST['iscorrect']) || $_POST['iscorrect'] == ""){
            echo "Sorry, important data to submit your question is missing. Please press back in your browser and try again and make sure you select a correct answer for the question.";
            exit();
        }

        if(!isset($_POST['type']) || $_POST['type'] == ""){
            echo "Sorry, there was an error parsing the form. Please press back in your browser and try again";
            exit();
        }

     //connecting to the database
        require_once("scripts/connect_db.php");

     //initializing the variables
        $question = $_POST['desc'];
        $program = $_POST['code_desc'];
        $programType = $_POST['prog-lang'];
        $answer1 = $_POST['answer1'];
        $answer2 = $_POST['answer2'];
        $answer3 = $_POST['answer3'];
        $answer4 = $_POST['answer4'];
        $type = $_POST['type'];
        $quizID = $_POST['quizID'];

     //replacing everything except 0-9 with nothing as its values are - 1/2/3...
        $quizID = preg_replace('/[^0-9]/', "", $quizID);

     //replacing everything except a-z with nothing as its values are - mc/tf
        $type = preg_replace('/[^a-z]/', "", $type);

     //replacing everything except 0-9 & a-z with nothhing as value is - answer1/2/3/4
        $isCorrect = preg_replace('/[^0-9a-z]/', "", $_POST['iscorrect']);

     //getting and converting strings as they are
        $question = htmlspecialchars($question);
        $question = mysqli_real_escape_string($con,$question);

        $program = htmlspecialchars($program);
        $program = mysqli_real_escape_string($con,$program);

        $answer1 = htmlspecialchars($answer1);
        $answer1 = mysqli_real_escape_string($con,$answer1);

        $answer2 = htmlspecialchars($answer2);
        $answer2 = mysqli_real_escape_string($con,$answer2);

        $answer3 = htmlspecialchars($answer3);
        $answer3 = mysqli_real_escape_string($con,$answer3);

        $answer4 = htmlspecialchars($answer4);
        $answer4 = mysqli_real_escape_string($con,$answer4);



     //if its a true/false question, do this-
        if($type == 'tf'){
         //if any field is null or empty, say sorry
            if((!$question) || (!$answer1) || (!$answer2) || (!$isCorrect)){
                if($answer1=='0' || $answer2=='0')
                {
                    //do nothing
                }else{
                    echo "Sorry, All fields must be filled in to add a new question to the quiz. Please press back in your browser and try again.";
                    exit();
                }
            }
        }

     //if its a multiple choice question, do this-
        if($type == 'mc'){
         //if any field is null or empty, say sorry
            if((!$question) || (!$answer1) || (!$answer2) || (!$answer3) || (!$answer4) || (!$isCorrect)){
                if($question=='0' || $answer1=='0' || $answer2=='0' || $answer3=='0' || $answer4=='0')
                {
                    //do nothing
                }else{
                    echo "Sorry, All fields must be filled in to add a new question to the quiz. Please press back in your browser and try again.";
                    exit();
                }
            }
        }

     //inserting the question and type into table question
        $sql = mysqli_query($con,"INSERT INTO questions (quiz_id, question, code, code_type, type) VALUES ('$quizID', '$question', '$program', '$programType', '$type')")or die(mysqli_error());
        //lastId is there, so we can insert the id, question_id in our table
            $lastId = mysqli_insert_id();
            mysqli_query($con,"UPDATE questions SET question_id='$lastId' WHERE id='$lastId' LIMIT 1")or die(mysqli_error());

它应该做什么：（示例）生成的测验ID

INSERT INTO `quizes` (`id`, `quiz_id`, `quiz_name`, `total_questions`, `display_questions`, `time_allotted`, `set_default`) VALUES
(1, 1, 'LEVEL1(EASY)', 22, 20, 30, 0),
(2, 2, 'LEVEL2(HARD)', 9, 10, 20, 1);

和问题：（应该做什么）

INSERT INTO `questions` (`id`, `quiz_id`, `question_id`, `question`, `code`, `code_type`, `type`) VALUES
(1, 1, 1, 'If the output of the question is  hai , find the error in the program?', 'main()\r\n { \r\nprintf("\\nab");\r\nprintf("\\bsi");\r\nprintf("\\aha");\r\n\r\n}\r\n', 'cpp', 'mc'),
(2, 1, 2, 'find the output?', 'void main()\n{\nint i=1,y;\ny=i---i---i;\ncout<<y<<â€,â€<<i;\ngetch();\n}\n', 'cpp', 'mc'),
(3, 1, 3, 'find the output?', '#include<stdio.h>\r\n\r\nint main()\r\n{\r\ncharstr[20], *s;\r\nprintf("Enter a string\\n");\r\nscanf("%s", str);\r\n    s=str;\r\nwhile(*s != ''\\0'')\r\n    {\r\nif(*s >= 97&& *s <= 122)\r\n            *s = *s-32;\r\n        s++;\r\n    }\r\nprintf("%s",str);\r\nreturn0;\r\n}\r\n', 'cpp', 'mc'),
(4, 1, 4, 'find the error', '#include<stdio.h>\r\nint main()\r\n{\r\nint P = 10;\r\nswitch(P)\r\n    {\r\ncase10:\r\nprintf("Case 1");\r\n\r\ncase20:\r\nprintf("Case 2");\r\nbreak;\r\n\r\ncase P:\r\nprintf("Case 2");\r\nbreak;\r\n    }\r\nreturn0;\r\n}\r\n\r\n', 'cpp', 'mc'),
(5, 1, 5, 'find the correct valid function call...assuming the function exists', '', '', 'mc'),

相反，对于Quizid和questionID，它只是在数据库中注册为0。

任何人都可以为我指出正确的方向以解决此问题，或提出其他建议。

以下是用于插入答案的代码（同样在admin.php中）

//if inserting a true/false question, insert answers by this-
        if($type == 'tf'){
         //if answer1 is marked correct, do this--
            if($isCorrect == "answer1"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }
         //if answer2 is marked correct, do this--
            if($isCorrect == "answer2"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }   
        }

     //if inserting a multiple choice question, insert answers by this-
        if($type == 'mc'){
         //if answer1 is marked correct, do this--
            if($isCorrect == "answer1"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer3', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer4', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }
         //if answer2 is marked correct, do this--
            if($isCorrect == "answer2"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer3', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer4', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }
         //if answer3 is marked correct, do this--
            if($isCorrect == "answer3"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer3', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer4', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }
         //if answer4 is marked correct, do this--
            if($isCorrect == "answer4"){
                $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer4', '1')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer1', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer2', '0')")or die(mysqli_error());
                mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES ('$quizID', '$lastId', '$answer3', '0')")or die(mysqli_error());
                $msg = 'Thanks, question no.'.$lastId.' has been added';
                header('location: admin.php?msg='.$msg.'');
                exit();
            }

整体表结构

图片附：

更新：根据下面的注释，还包括添加到测验表中的代码

<?php

    include('scripts/connect_db.php');

        if(isset($_POST['quizName']) && $_POST['quizName'] != ""
        && isset($_POST['quizTime']) && $_POST['quizTime'] != ""
        && isset($_POST['numQues']) && $_POST['numQues'] != ""){

            $qName=mysql_real_escape_string($_POST['quizName']);
            $qTime=mysql_real_escape_string($_POST['quizTime']);
            $nQues=mysql_real_escape_string($_POST['numQues']);

            $qTime = preg_replace('/[^0-9]/', "", $qTime);
            $nQues = preg_replace('/[^0-9]/', "", $nQues);

            $fetch=mysql_query("SELECT id FROM quizes 
                                WHERE quiz_name='$qName'")or die(mysql_error());
            $count=mysql_num_rows($fetch);
            if($count!="")
            {
                $user_msg = 'Sorry, but \ '.$qName.' \ already exists!';
                header('location: admin.php?msg='.$user_msg.'');
            }else{
                mysql_query("INSERT INTO quizes (quiz_name, display_questions, time_allotted) 
                    VALUES ('$qName','$nQues','$qTime')")or die(mysql_error());

                $lastId = mysql_insert_id();
                mysql_query("UPDATE quizes SET quiz_id='$lastId' 
                                WHERE id='$lastId' LIMIT 1")or die(mysql_error());

                $user_msg = 'Quiz, \ '.$qName.' \ has been created!';
                header('location: admin.php?msg='.$user_msg.'');
            }
        }else{
            $user_msg = 'Sorry, but Something went wrong';
            header('location: admin.php?msg='.$user_msg.'');
        }
?>

Answer 1

首先，行数将是数字，因此：

if($count!="")

确实应该是：

if($count > 0)

接下来，您应该使用mysqli扩展名或PDO。 mysql_函数已经过时了一段时间，在新版本的PHP中已被完全删除，因此如果不进行转换，代码将中断。

最后，您似乎将“ id”作为自动递增的主键，但是您将立即将该值复制到quiz_id字段中。 这浪费了查询，并使要使用哪个字段的水变得混乱。 您可能应该摆脱quiz_id并使用if（或将id重命名为quiz_id）

为了获得更好的性能和可靠性，只需在测验名称字段中添加唯一索引。 然后，您可以尝试插入测验表，而无需进行名称检查。 如果由于名称重复而失败，该错误将告诉您已经有该名称的记录。 然后，您可以摆脱多余的SELECT。

编辑：如果您询问唯一索引部分，基本上在quiz_name字段上添加唯一索引的SQL将是：

ALTER TABLE `quizes`
ADD UNIQUE INDEX `quiz_name` (`quiz_name`);

然后，代码如下所示：

...
$qTime = preg_replace('/[^0-9]/', "", $qTime);
$nQues = preg_replace('/[^0-9]/', "", $nQues);
// End of original code

$result = mysql_query("INSERT INTO quizes (quiz_name,...other fields...) VALUES ('Quiz A',...other values...)");
if(!$result)
{
  // Failed to insert new quiz
  $error_msg = mysql_error();

  // Check the content of the error message
  if(strpos($error_msg,"Duplicate entry") !== false)
  {
    // A quiz with that name already exists, redirect to the admin page with the desired message
  }
  else
  {
    // Some other error happened, redirect to the admin page with the desired message
  }
}
else
{
  // Successful quiz insert
  $newQuizID = mysql_insert_id();
  echo $newQuizID . "\n";
}

重要提示：我使用“ mysql_”函数只是为了与您现在拥有的功能保持一致，但是我不能强调强调转换为mysqli或PDO的重要性。 最简单的转换可能是mysqli，因为语法非常相似。

编辑＃2：此外，对您的代码进行了另一种优化，可以插入多项选择答案-您可以提高INSERT性能，并简化代码，如下所示：

if($type == 'mc'){
  $sql2 = mysqli_query($con,"INSERT INTO answers (quiz_id, question_id, answer, correct) VALUES 
      ('$quizID', '$lastId', '$answer1', '". ($isCorrect == "answer1" ? "1" : "0") ."'),
      ('$quizID', '$lastId', '$answer2', '". ($isCorrect == "answer2" ? "1" : "0") ."'),
      ('$quizID', '$lastId', '$answer3', '". ($isCorrect == "answer3" ? "1" : "0") ."'),
      ('$quizID', '$lastId', '$answer4', '". ($isCorrect == "answer4" ? "1" : "0") ."')") or die(mysqli_error());
  $msg = 'Thanks, question no.'.$lastId.' has been added';
  header('location: admin.php?msg='.$msg.'');
  exit();
}

该代码将使用一次插入多个行的MySQL功能，以便您仅运行一个查询而不是4，并且使用一些基本的PHP为“正确”列选择“ 1”或“ 0”。