Can't insert form data into database (MySQLIi) - php

Question

EDIT: I'm not sure what to really say. The comments was what helped my issue out right now. I didn't remember the fact to show an error, and that was what helped me. I had pretty much just tried something that obviously wasn't working due to wrongly placed variables and such,and displaying the error code let me know what variables was the faulty ones. Thank you for all your help, and this issue is now resolved!
So long story short, the title. I have no idea why this code refuses to input the inserted data into the database, and I've tried a bunch of things that haven't resulted any better.
Connection:
<?php
session_start();
$host = 'host';
$dbusername = 'username';
$dbpassword = 'password';
$anslutning = mysqli_connect($host, $dbusername, $dbpassword) or die("<b>Could not connect to database server</b>");
$anslutning->select_db('databasename') or die("<b>Could not connect to the specified database</b>");
?>
Form to grab data from :
echo '
<h2><center>Post a topic</center></h2>
<br /><br />
<div class="indexform">
<form action="index.php" method="POST">
Title: <input type="text" name="title"> <br /> <br />
Content: <textarea name="content" class="content"> </textarea>
<br /> <br />
<input type="submit" name="postTopicOnGeneral">
</form>
</div>
';
PHP code to insert it into database
if(isset($_POST['postTopicOnGeneral'])) {
$username = $_POST['username'];
$title = $_POST['title'];
$content = $_POST['content'];
$general = $_POST['general'];
$addPostOnGeneral = $anslutning->prepare('INSERT INTO tblPosts(title, content, author, category) VALUES(?, ?, ?, ?)');
$addPostOnGeneral->bind_param("ssss", $title, $content, $username, $general);
$addPostOnGeneral->execute();
echo "<center>Post created!</center>";
sleep(2);
echo "<script> window.location.href = 'index.php?general=1' </script>";
}

Answer 1

Undefined index:username and Undefined:general is what I get from that.
You are bound to get that error since you are not fetching $username and $general from anywhere in your form.
Change your form this:
echo '
<h2><center>Post a topic</center></h2>
<br /><br />
<div class="indexform">
<form action="index.php" method="POST">
Title: <input type="text" name="title"> <br /> <br />
Content: <textarea name="content" class="content"> </textarea>
<br /> <br />
<input type="submit" name="postTopicOnGeneral">
</form>
</div>';
to this:
echo '
<h2><center>Post a topic</center></h2>
<br /><br />
<div class="indexform">
<form action="index.php" method="POST">
Title: <input type="text" name="title"> <br /> <br />
Content: <textarea name="content" class="content"> </textarea>
<br /> <br />
Username:
<input type="text" name="username">
General:
<input type="text" name="general">
<input type="submit" name="postTopicOnGeneral">
</form>
</div>';
And then in your index.php:
if(isset($_POST['postTopicOnGeneral'])) {
echo $username = $_POST['username'];
echo $title = $_POST['title'];
echo $content = $_POST['content'];
echo $general = $_POST['general'];
// rest of your code

Answer 2

Try to change
$username = $_POST['username'];
$title = $_POST['title'];
$content = $_POST['content'];
$general = $_POST['general'];
With this:
$username = isset($_POST['username']) ? $_POST['username'] : '';
$title = isset($_POST['title']) ? $_POST['title'] : '';
$content = isset($_POST['content']) ? $_POST['content'] : '';
$general = isset($_POST['general']) ? $_POST['general'] : '';