Three voting blocks: STOPPING the same answer from being chosen twice

[Mike_Smith]

Hi everyone, I recently had a php problem for a script I'm writing and had some great help from the forum here and am back with another brain stumper. I've dug into the codes, added/edited/removed and have my codes set where I need them.

However, the code is showing three random results from the database and each result gets three options to choose from (spoon, fork, knife). What I need to figure out is a way to make sure each image thats showing up gets one vote - and the person cannot vote on the same answer for pic2 and pic3 (ie: if they vote "spoon" for pic1, I need it to give a "please vote again" message if they click the same answer for pic2 or pic3).

Here's my index.php code

<?php 
// Connects to your Database 
$link = mysql_connect('localhost', 'username', 'password'); 
mysql_select_db("database") or die(mysql_error()); 

?>

<?php include('header.php'); ?>

<div class="contentwide">
	<div class="contentwrap">
<form method="post" action="voted.php"> 
<?php 
$query = "SELECT id, name, url FROM photos WHERE category!= 'Xrated' ORDER BY RAND() LIMIT 3";
$result = mysql_query($query); 
while($row = mysql_fetch_assoc($result)) 
{ 
?> 
    <input type="hidden" name="id[]" value="<?php echo $row['id']; ?>">
    <input type="hidden" name="page" value="index.php"> 
    <div class="picturewrap"> 
        <img src="<?php echo $row['url']; ?>" alt="<?php echo $row['name']; ?>" /> 
        <div class="formwrapper"> 
		     <div class="formspoon">
		     <img src="images/form_spoon.jpg" alt="" /><br />
		     <input type="radio" name="images[<?php echo $row['id']; ?>]" value="1"> 
		     </div>
        </div> 
        <div class="formwrapper"> 
		     <div class="formspoon">
		     <img src="images/form_knife.jpg" alt="" /><br />
		     <input type="radio" name="images[<?php echo $row['id']; ?>]" value="3"> 
		     </div>
        </div> 
        <div class="formwrapper"> 
                 <div class="formspoon">
		     <img src="images/form_fork.jpg" alt="" /><br />
		     <input type="radio" name="images[<?php echo $row['id']; ?>]" value="2"> 
		     </div>
        </div> 
    </div> 
<?php 
} 
?> 
    <div class="submitform"> 
        <input type="image" src="images/button_submit.jpg" class="button_submit" value="Submit"><br/ > 
    </div> 
</form> 
	</div>
</div>
<?php mysql_close($link); ?>
<?php include('footer.php'); ?>

Here is my voted.php file

<?php 

// Connects to your Database 
$link = mysql_connect('localhost', 'user', 'password'); 
mysql_select_db("database") or die(mysql_error()); 

$page = $_POST['page']; 

if ( !empty( $_POST['images'] ) ) { 
    $images = $_POST['images']; 
    // Loop over each item in the $images array. 
    foreach ( $images as $id => $vote ) { 
        if ( $vote == 1 ) { 
            $update = sprintf( "UPDATE photos SET spoon=spoon+1 WHERE id=$id", $vote , $id ); 
            mysql_query( $update ) OR DIE( "error in query" );
		header("Location: $page");  

        } elseif ( $vote == 2 ) { 
            $update = sprintf( "UPDATE photos SET fork=fork+1 WHERE id=$id", $vote , $id ); 
            mysql_query( $update ) OR DIE( "error in query" ); 
		header("Location: $page"); 
        } elseif ( $vote == 3 ) { 
            $update = sprintf( "UPDATE photos SET knife=knife+1 WHERE id=$id", $vote , $id ); 
            mysql_query( $update ) OR DIE( "error in query" ); 
		header("Location: $page"); 
        } else 
            die( "Invalid value passed as a vote." ); 
    } 
} 

?>

Any ideas? (the site is being built similar to www.fmarrykill.net if you'd like to see a live working example of how the "don't vote twice" thing goes.

Thanks for any help you can give me. I'm starting to get the hang of php and I have to say, I really enjoy it and also am grateful that this forum is here to help guide me 🙂

[djjjozsi]

you need to store the votes in another table, suggested normalization rules can be found here
Vote results not suggested to store in the images table, becouse you cannot track the visitor's choices if you increment some kind of a counter only.

You need to save the random combinations somewhere, into a new table, each image(ID) into a new row, call it combinations table, where you store the random images primary KEYS from the images table.

normalization has sense if you build votes scripts from a bounch of images.

In my previous post i mentioned this problem with the users tracking.

[Mike_Smith]

So I'd need to set up a new table "combinations" and have two columns in it "id(for the pics)" and "random" right? How would I get that to pop up a message telling the visitor to "select a different answer" if they're voting the same option for two pics (ie: pic2 and pic3 both get the "spoon" option clicked).

[djjjozsi]

if you have the images table:
1 orange.jpg
2 apple.jpg
3 plane.jpg

then save the votes in a votes table:
image_id , session_id , vote
1 , 0000000000000000 , spoon
2 , 0000000000000000 , folk
3 , 0000000000000000 , something

mysql has features to define unique key for determined fields, such as:
image_id + session_id + vote must have been unique. So i can't select spoon twice for the images.

how to solve that the user cannot vote with the same answer, set another unique key for the sessionID and vote, if the user gives the same answer you will get duplicate entry error after your INSERT command. But something is wrong here. If a user gives another vote with the spoon, this cause error. The mentioned definition table could solve this problem.

the user add the votes, press the submit button, and you fill the imageID 's into the definition table.
definition table:
def_id , image1_id , image2_id , image2_id

you will get the new def_id with the mysql_insert_id()

Take a new field into the votes table, called: def_id

Now votes looks like:
def_id , image_id , session_id , vote
1 , 1 , 0000000000000000 , spoon
1 , 2 , 0000000000000000 , folk
1 , 3 , 0000000000000000 , something

if you set unique to the def_id + session_id + vote fields, if the user gives the same vote for that random list, that will cause DUplicate Entry error on Insert, and you can make an error message, try to give another answer, and delete the inserted votes.

This idea might gives you better ideas how to solve this problem. Notice that, this is a half solution only. If you want to build a vote system for unlimited items, you should build a norlamized table structure for the defintions table.

[Mike_Smith]

THANKS 🙂 I'm going to spend some time on this and see if I can figure out how to wrap it all in together. I appreciate your help a lot.