阻止输入框中的空值插入我的数据库？ PHP答案

【问题标题】：Stop empty values from input boxes from being inserted into my database? PHP阻止输入框中的空值插入我的数据库？ PHP
【发布时间】：2013-08-07 05:11:26
【问题描述】：

这是html表单（register.php）：

<html>
<body>

<form action="handle_registration.php" method="post">

<fieldset><legend>Enter your
information in the form below:</legend>

First Name: <input type="text" name="fname" size="20" maxlength="40"><br>
Last Name: <input type="text" name="lname" size="20" maxlength="40"><br>
Username: <input type="text" name="uname" size="20" maxlength="40"><br>
Password: <input type="text" name="pword" size="20" maxlength="40"><br>
<input type="submit" name="submit" value="submit my info">

</form>

</body>
</html>

这是处理注册的php脚本（handle_registration.php）：

<?php

// Create a shorthand for the form data:

$fname = $_POST['fname'];
$lname = $_POST['lname'];
$uname = $_POST['uname'];
$pword = $_POST['pword'];

// Create the connection variables:

$db_host = "localhost";
$db_user = "root";
$db_pass = "";
$db_name = "registration_info";
$con = mysqli_connect("$db_host", "$db_user", "$db_pass", "$db_name");

// Check the connection:

if (mysqli_connect_errno ())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// Make sure all of the input boxes have a value:

if (empty($fname)) {
die('You forgot to enter your first name!');
}

if (empty($lname)) {
die('You forgot to enter your last name!');
}

if (empty($uname)) {
die('You forgot to choose a username!');
}

if (empty($pword)) {
die('You forgot to choose a password!');
}

// Insert the data from the form into the DB:

$sql = "INSERT INTO basic_information (First_Name, Last_Name, Username, Password)
VALUES
('$_POST[fname]', '$_POST[lname]', '$_POST[uname]', '$_POST[pword]')";

// Enter the info the end user type if everything is ok:

if (!mysqli_query($con,$sql))
{
die('Error: ' . mysqli_error($con));
}
else
{
echo "Record has been added";
}

// Close the connection:

mysqli_close($con);

?>

问题来了：

如果所有输入字段都有值，我想将输入的值提交到我的数据库中，但是当我在检查它们是否为空后使用 die 函数时，它会终止脚本。如果一个或多个字段为空，我只想杀死部分将其插入我的数据库并显示一条错误消息，告知哪个字段为空。我不知道如何解决这个问题，任何帮助将不胜感激。

【问题讨论】：

参考这个网址：w3schools.in/php-tutorial/form-validation
1.将所有错误存储在一个数组中。如果数组为空，则插入数据库，否则打印数组内容。
您可能会收到一些 cmets，告诉您注意 SQL 注入和安全性。这也是您应该关注的一个问题。另一个问题是，检查表单字段的来源是否是一个更好的主意，即通过客户端浏览器中的一些 JavaScript/jQuery 验证器。通过这种方式，您可以在出现错误（或缺失值）时为用户提供更快的响应，并避免来自服务器的不必要流量。

标签： php forms mysqli registration

【解决方案1】：

解决方案相当简单。只需将错误消息存储在变量中，然后在将行插入数据库之前 - 检查天气是否设置了错误或者它是否为空。如果它是空的 - 我们可以插入该行。否则 - 让我们显示错误消息。

// Currently we do not have an error
$error = NULL;

// Validate
if (empty($pword)) {
    $error = 'You forgot to choose a password!';
}

// If there are no errors - lets insert
if (!$error) {
    $sql = 'INSERT INTO ...';
}

【讨论】：

【解决方案2】：

不要使用 die ，使用一些变量来存储错误并稍后打印出来

 <?php

 // Create a shorthand for the form data:

 $fname = $_POST['fname']; $lname = $_POST['lname']; $uname =
$_POST['uname']; $pword = $_POST['pword'];

// Create the connection variables:

 $db_host = "localhost"; $db_user = "root"; $db_pass = ""; $db_name =
 "registration_info"; $con = mysqli_connect("$db_host", "$db_user",
 "$db_pass", "$db_name");

 // Check the connection:

 if (mysqli_connect_errno ()) { echo "Failed to connect to MySQL: " .
 mysqli_connect_error(); }

 // Make sure all of the input boxes have a value:

 if (empty($fname)) { $error_msg[]='You forgot to enter your first name!'; }

 if (empty($lname)) { $error_msg[]='You forgot to enter your last name!'; }

 if (empty($uname)) { $error_msg[]='You forgot to choose a username!'; }

 if (empty($pword)) { $error_msg[]='You forgot to choose a password!'; }

 // Insert the data from the form into the DB:
 if(count($error_msg)==0){
 $sql = "INSERT INTO basic_information (First_Name, Last_Name,
 Username, Password) VALUES ('$_POST[fname]', '$_POST[lname]',
 '$_POST[uname]', '$_POST[pword]')";

 // Enter the info the end user type if everything is ok:

 if (!mysqli_query($con,$sql)) { die('Error: ' . mysqli_error($con)); }
 else { echo "Record has been added"; }

 // Close the connection:

 mysqli_close($con);
}else{
print_r($error_msg);
}

 ?>

【讨论】：

【解决方案3】：

停止插入空数据的完整工作示例

<?php
          if (isset($_POST["submit"])) {
              $emptyInput = NULL;
              if (!($_POST["firstname"] == $emptyInput or $_POST["lastname"] == $emptyInput or $_POST["email"] == $emptyInput)) {
                  $sql = "INSERT INTO MyGuests (firstname, lastname, email) VALUES ('" . $_POST["firstname"] . "','" . $_POST["lastname"] . "','" . $_POST["email"] . "')";
                  if (mysqli_query($conn, $sql)) {
                      echo 'Record inserted successfully!';
                  }
              } else {
                  echo 'all fields are compulsory!';
              }
          }
          ?>

【讨论】：

【解决方案4】：

您可以使用 $errors 变量来保存所有字段的错误

$error = array();//initializing the $error
if (empty($fname)) {
$error[] = 'You forgot to enter your first name!';
}

if (empty($lname)) {
$error[] = 'You forgot to enter your last name!';
}

if (empty($uname)) {
$error[] = 'You forgot to choose a username!';
}

if (empty($pword)) {
$error[] = 'You forgot to choose a password!';
}

if(!empty($error))//if error occured
{
   die(implode('<br />', $error));//Stops the script and prints the errors if any occured
}
// Insert the data from the form into the DB:

$sql = "INSERT INTO basic_information (First_Name, Last_Name, Username, Password)
VALUES
('$_POST[fname]', '$_POST[lname]', '$_POST[uname]', '$_POST[pword]')";

// Enter the info the end user type if everything is ok:

if (!mysqli_query($con,$sql))
{
die('Error: ' . mysqli_error($con));
}
else
{
echo "Record has been added";
}

// Close the connection:

mysqli_close($con);

【讨论】：