我正在尝试做一个在数据库（MySQL）中注册用户的注册表

Question

Question:I am trying to do a registration form that registers a user in a database (MySQL).
The code is supposed to register: - username - password - first name - last name - email

And I am getting errors like this:

Notice: Undefined index: fname in C:\xampp\htdocs\Railways\reg.php on line 89

Notice: Undefined index: lname in C:\xampp\htdocs\Railways\reg.php on line 90

Notice: Undefined index: uname1 in C:\xampp\htdocs\Railways\reg.php on line 91

Notice: Undefined index: pswrd1 in C:\xampp\htdocs\Railways\reg.php on line 92

Notice: Undefined index: email in C:\xampp\htdocs\Railways\reg.php on line 93

Fatal error: Call to a member function query() on null in C:\xampp\htdocs\Railways\reg.php on line 98

Here is the code:

<?php
    global $conn;
    include_once('connect.php');
        $first=$_POST['fname'];
        $last=$_POST['lname'];
        $usernam=$_POST['uname1'];
        $passwrd=$_POST['pswrd1'];
        $email=$_POST['email'];
    $sql=" INSERT INTO users(username,password,firstname,lastname,email) VALUES ('".$usernam."','".$passwrd."','".$first."','".$last."','".$email."')";
    if($conn->query($sql))
    {
        echo "<h1 style='text-align:center'> Registered Succesfully </h1>";
    }
    else
    {
        echo "<h1 style='text-align:center' id='text'>Error</h1>";
        echo $conn->connect_error;
    }
?>

And here is the HTML:

<form  action="reg.php" method="POST">
    <label id="text"> Firstname: <br> <br> <input id="input" type="text" name="fname" placeholder="Firstname" id="t3"> </label>
    <br> <br> <br>
    <label id="text"> Lastname: <br> <br> <input id="input" type="text" name="lname" placeholder="Lastname" id="t4"> </label>
    <br> <br> <br>

    <label id="text"> Username: <br> <br> <input id="input" type="text" name="uname1" placeholder="Username" id="t1"> </label>
    <br> <br> <br>

    <label id="text"> Password: <br> <br> <input id="input" type="text" name="pswrd1" placeholder="Password" id="t2"> </label>
    <br> <br> <br>

    <label id="text"> Email: <br> <br> <input id="input" type="text" name="email" placeholder="Email" id="t1"> </label>
    <br> <br> <br>

    <input style="background-color:red;padding:7px;margin-left:40px;"type="submit" value="Register" name="submit" id="s1">

    </td></tr>
    </table>
    </div>
</form>

connect.php code

    <?php

          $conn_error="could not connect";
          $host="localhost";
          $user="root";
          $pass="";
          $db="railways";
        $sql =mysqli_connect($host,$user,$pass,$db) or die($conn_error);
        echo'conneced';

?>

Answer 1

Add a check if post submit is set then run your query otherwise if you open this page directly $_POST variable is empty and reason of you get error is your $_POST array is empty.

<?php


include_once('connect.php');
global $conn;
if(isset($_POST['submit'])) // this check
{
    $first=$_POST['fname'];
    $last=$_POST['lname'];
    $usernam=$_POST['uname1'];
    $passwrd=$_POST['pswrd1'];
    $email=$_POST['email'];


$sql=" INSERT INTO users(username,password,firstname,lastname,email) VALUES ('".$usernam."','".$passwrd."','".$first."','".$last."','".$email."')";

if($conn->query($sql))
  {
    echo "<h1 style='text-align:center'> Registered Succesfully </h1>";

  }
else
  {
    echo "<h1 style='text-align:center' id='text'>Error</h1>";
    echo $conn->connect_error;
  }
}
?>

Answer 2

You need to define those values to something if $_POST is not set.

Something like this:

$first=isset($_POST['fname']) ? $_POST['fname'] : "" ;
$last=isset($_POST['lname']) ? $_POST['lname'] : "";
$usernam=isset($_POST['uname1']) ? $_POST['unmae1'] : "";
$passwrd=isset($_POST['pswrd1']) ? $_POST['pswrd1'] : "";
$email=isset($_POST['email']) ? $_POST['email'] : "";

if(isset($_POST['submit'])){
  $sql=" INSERT INTO users(username,password,firstname,lastname,email) VALUES ('".$usernam."','".$passwrd."','".$first."','".$last."','".$email."')";

 if($conn->query($sql)){
    echo "<h1 style='text-align:center'> Registered Succesfully </h1>";
}
else{
    echo "<h1 style='text-align:center' id='text'>Error</h1>";
    echo $conn->connect_error;}
}