php - 如何避免查询加倍插入数据库？

Question

问题:
我制作了一个简单的表单，它使用 PHP 通过 INSERT 查询将信息传递到我的数据库。但是，每次我运行它时，它都会尝试将信息放入两次。我怎样才能避免这种情况？

解释:
我首先将答案插入到我的答案表中，将 AnswerID 保存为变量。然后使用我的问题表进行保存，最后我将包含 ID 的两个已保存变量用于我的问题_答案表中。

我的代码:

if (isset($_POST['textinput1']) && !empty($_POST['textinput1'])) {

      $text1 = mysqli_real_escape_string($conn, $_POST['textinput1']);
      $text2 = mysqli_real_escape_string($conn, $_POST['textinput2']);
      $q_text = mysqli_real_escape_string($conn, $_POST['textarea']);

      $stmt = $conn->prepare("INSERT INTO answers (Answer1Text, Answer2Text) VALUES (?, ?)");
      $stmt->bind_param('ss', $text1, $text2);
      $stmt->execute();
      $answerid = $stmt->insert_id;
      $stmt = $conn->prepare("INSERT INTO question (QuestionText) VALUES (?)");
      $stmt->bind_param('s', $q_text);
      $stmt->execute();
      $questionid = $stmt->insert_id;
      if ($stmt->execute()) {
        $stmt = $conn->prepare("INSERT INTO question_answers (AnswerID, QuestionID) VALUES (?, ?)");
        $stmt->bind_param('ss', $answerid, $questionid);
        $stmt->execute();
        echo "<h2>Dit spørgsmål er nu lagt op på siden!</h2>";
        echo "<h3>Tusinde tak for din interesse for SMIL - Skodfri Århus.</h3>";
      }
      else
      {
        echo "ERROR: Could not able to execute . " . mysqli_error($conn);
      }
    }

    // close connection
    mysqli_close($conn);
    ?>

我的重要表:
问题:QuestionID(PK)，QuestionText
答案:AnswerID(PK)、Answer1Text、Answer2Text
question_answers:QuestionAnswerID(PK)、QuestionID(FK)、AnswerID(FK)

附言。我不喜欢使用复合唯一约束作为解决方案。

还有一个附带问题，$stmt->insert_id 变量应该是 mysqli_real_escape_string 吗？

Answer 1

你的问题是你已经执行了两次查询

if (isset($_POST['textinput1']) && !empty($_POST['textinput1'])) {

      $text1 = mysqli_real_escape_string($conn, $_POST['textinput1']);
      $text2 = mysqli_real_escape_string($conn, $_POST['textinput2']);
      $q_text = mysqli_real_escape_string($conn, $_POST['textarea']);

      $stmt = $conn->prepare("INSERT INTO answers (Answer1Text, Answer2Text) VALUES (?, ?)");
      $stmt->bind_param('ss', $text1, $text2);
      $stmt->execute();
      $answerid = $stmt->insert_id;
      $stmt = $conn->prepare("INSERT INTO question (QuestionText) VALUES (?)");
      $stmt->bind_param('s', $q_text);
      $stmt->execute();
      $questionid = $stmt->insert_id;

      // THIS IS THE SECOND EXECUTION OF QUERY 2
      if ($stmt->execute()) {
        $stmt = $conn->prepare("INSERT INTO question_answers (AnswerID, QuestionID) VALUES (?, ?)");
        $stmt->bind_param('ss', $answerid, $questionid);
        $stmt->execute();
        echo "<h2>Dit spørgsmål er nu lagt op på siden!</h2>";
        echo "<h3>Tusinde tak for din interesse for SMIL - Skodfri Århus.</h3>";
      }
      else
      {
        echo "ERROR: Could not able to execute . " . mysqli_error($conn);
      }
    }

    // close connection
    mysqli_close($conn);
    ?>

改为尝试将此作为 IF 测试

    //if ($stmt->execute()) {
    if ( isset($answerid,$questionid) ) {