PHP Comparing variables returns false every time - php

Question

I have this script that checks a submitted form. It checks if all fields are all filled out, and checks if the user has submitted the form before. It also checks if the entered data is already in the database or not. When I try to check if the entered data is in the database, it always returns false. My question is: How can I efficiently check if the POST values are the same?
Code:
<?php
error_reporting(E_NOTICE ^ E_ALL);
$Name = $_POST['name'];
$ID = $_POST['id'];
$Topic_1 = $_POST['1'];
$Topic_2 = $_POST['2'];
$Topic_3 = $_POST['3'];
$Topic_4 = $_POST['4'];
$Topic_5 = $_POST['5'];
$Topic_6 = $_POST['6'];
$Topic_7 = $_POST['7'];
$Topic_8 = $_POST['8'];
$Topic_9 = $_POST['9'];
$Topic_10 = $_POST['10'];
$Topic_11 = $_POST['11'];
$Topic_12 = $_POST['12'];
$Topic_13 = $_POST['13'];
$Topic_14 = $_POST['14'];
$Topic_15 = $_POST['15'];
$IP = $_SERVER['REMOTE_ADDR'];
$Connect = new mysqli("127.0.0.1", "root", "", "Data");
$Check = 'SELECT * FROM Submissions WHERE School_ID = "'.$ID.'" AND IP = "'.$IP.'"';
$Insert = 'INSERT INTO Submissions (Name, School_ID, Topic_1, Topic_2, Topic_3, Topic_4, Topic_5, Topic_6, Topic_7, Topic_8, Topic_9, Topic_10, Topic_11, Topic_12, Topic_13, Topic_14, Topic_15, IP) VALUES ("'.$Name.'", "'.$ID.'", "'.$Topic_1.'", "'.$Topic_2.'", "'.$Topic_3.'", "'.$Topic_4.'", "'.$Topic_5.'", "'.$Topic_6.'", "'.$Topic_7.'", "'.$Topic_8.'", "'.$Topic_9.'", "'.$Topic_10.'", "'.$Topic_11.'", "'.$Topic_12.'", "'.$Topic_13.'", "'.$Topic_14.'", "'.$Topic_15.'", "'.$IP.'")';
if($Name && $ID != "")
{
if($Result = $Connect->query($Check))
{
$Rows = $Result->num_rows;
if($Rows == 0)
{
if($_POST != $_POST)
{
if($Go = $Connect->prepare($Insert))
{
if($Go->execute())
{
echo 'Thanks';
}
else
{
echo 'There Was An Error';
}
}
else
{
echo 'There Was An Error';
}
}
else
{
echo 'No Two Values Can Match.';
}
}
else
{
echo 'You Cant Vote Twice.';
}
$Result->close();
}
else
{
echo 'There Was An Error.';
}
}
else
{
echo 'Please Fill Out All Fields';
}
$Connect->close();

Answer 1

Your if statement should look like
if($name != "" && $check != "")

Answer 2

Here's the error:
if($_POST != $_POST)
You do probably want to compare the result from the db with the $_POST instead.
$Row = $Result->fetch_assoc();
if($Row != $_POST)

Answer 3

Prior to doing a comparison use var_dump() on the variables to check what they actually contain.
var_dump($Name);
var_dump($ID);
exit();
Then check for a negative or positive match.
if( !empty($Name) && empty($ID) ){
exit('ah, name filled in but not id ...');
}
You can even spoof that in a separate file.
<?php
$Name = 'Bob';
$ID = ''; // or use 0 or any test you want
var_dump($Name);
var_dump($ID);
if( !empty($Name) && empty($ID) ){
exit('ah, name filled in but not id ...');
}
Isolating problems like this will help you develop incrementally, get something working, then add more lines till you arrive at your destination.

Answer 4

To check if not two POST values are the same:
array_diff($_POST, array_unique($_POST));

Answer 5

What you looking for is following
$_POST['1'] = 'a';
$_POST['2'] = 'b';
$_POST['3'] = 'c';
$_POST['4'] = 'a';
$_POST['5'] = 'd';
$results = array_unique($_POST);
var_dump($results);
returns:
array
1 => string 'a' (length=1)
2 => string 'b' (length=1)
3 => string 'c' (length=1)
5 => string 'd' (length=1)

Answer 6

You can't really so easily check if a person did submit a form before.
One way is to add one more hidden field to form if the request came with POST.
Something like that:
<form method="POST" action="">
<?php
if(isset($_POST['submit'])) {
echo '<input type="hidden" name="second_post" value="1">';
} ?>
<!-- Other form items -->
<input type="submit" name="submit" value="1">
</form>
Then you can check is it a second time with:
if(isset($_POST['second_post'])) {
// Second time of form post;
} else {
// First (or zero) time post.
}