Increase in Value button "mrk2" - php

Question

Update post for: Increase in Value button
I made a post asking about how make an increase value button. I got one decent answer, I tried it and it didn't work.
Original:
$result = mysqli_query($con, "SELECT * FROM champion_counters_b WHERE champion_name='" . $search_result . "'");
echo "<table class='champion_counters' border='1'><tr><th>Champion Counter</th><th>Up Votes</th><th>Down Votes</th></tr>";
while($row = mysqli_fetch_array($result)) {
echo "<tr>";
echo "<td>" . $row['champion_counter'] . "</td>";
echo "<td>" . $row['upvotes'] . "</td>";
echo "<td>" . $row['downvotes'] . "</td>";
}
echo "</table>";
Current:
$result = mysqli_query($con, "SELECT * FROM champion_counters_b WHERE champion_name='" . $search_result . "'");
echo "<table class='champion_counters' border='1'><tr><th>Champion Counter</th><th>Up Votes</th><th>Down Votes</th></tr>";
while($row = mysqli_fetch_array($result)) {
echo "<tr>";
echo "<td>" . $row['champion_counter'] . "</td>";
echo "<td><a href='action.php?do=up&id=" . $row['upvotes'] . "'>Upvote [" . $row['upvotes'] . "]</a></td>";
echo "<td><a href='action.php?do=down&id=" . $row['downvotes'] . "'>Downvote [" . $row['downvotes'] . "]</a></td>";
}
echo "</table>";
mysqli_close($con);
?>
action.php:
$action = $_GET['do'];
$id = $_GET['id'];
if ($action=="up") {
$result = mysqli_query($con, "UPDATE champion_counters_b SET" . $id . "=" . $id+1 . "'");
}
elseif ($action=="down") {
$result = mysqli_query($con, "UPDATE champion_counters_b SET" . $id . "=" . $id-1 . "'");
}
else {echo "error: 002 / voting error";}
mysqli_close($con);
?>
As you can see I implemented the changes that were recommended and that could of worked, but they didn't rather than updating the data it did nothing. As when pressing "upvote"/"downvote" it grabbed the current value as $id rather than the position of the data to update it.
tl;dr: I tried a fix from the previous thread, it didn't do anything. Help please?

Answer 1

sorry if I have been unclear, let me give it another try:
You insert a link into your table, which calls an action.php. The action.php updates the database. The information needed for updating are passed as GET-parameters.
For updating the database, you will need to know WHAT to do, and secondly, WHICH database entry is actually affected.
Step by step:
First, you have to insert the links into your table:
$result = mysqli_query($con, "SELECT * FROM champion_counters_b WHERE champion_name='" . $search_result . "'");
echo "<table class='champion_counters' border='1'><tr><th>Champion Counter</th><th>Up Votes</th><th></th><th>Down Votes</th><th></th></tr>";
while($row = mysqli_fetch_array($result)) {
echo "<tr>";
echo "<td>" . $row['champion_counter'] . "</td>";
echo "<td>" . $row['upvotes'] . "</td>";
echo "<td><a href='action.php?do=up&id=" . $row['key'] . "'>Upvote</a></td>";
echo "<td>" . $row['downvotes'] . "</td>";
echo "<td><a href='action.php?do=down&id=" . $row['key'] . "'>Downvote</a></td>";
echo "</tr>";
}
echo "</table>";
On clicking the link, we are sending two pieces of information to the action.php.
The action we have to perform, either up- or downvoting. It tells us WHAT to do.
The id of the element we have to up- or downvote. The id tells us WHICH element is affected, and not the number of votes an element has.
As mentioned in my answer to your previous post, $row['key'] should contain the primary key of your database, e.g. an unique identifier. You should have such an identifier in your database, otherwise you cannot make a reference to a specific database entry. However, as we want to update the vote count for a very specific database entry, we need a possibility to uniquely identify this database entry.
In your action.php, you have to do the following:
$action = $_GET['do'];
$id = $_GET['id'];
if ($action=="up") {
mysqli_query($con, "UPDATE champion_counters_b SET upvotes = upvotes + 1 WHERE key = " . $id . "'");
}
elseif ($action=="down") {
mysqli_query($con, "UPDATE champion_counters_b SET downvotes = downvotes - 1 WHERE key = " . $id . "'"); }
else {echo "error: 002 / voting error";}
mysqli_close($con);
We use the id value to select the database entry we have to update. This is done by WHERE key = $id in the UPDATE-statement. The current vote count is taken from the database itself - there is no need to pass the current vote count in the GET-parameters.
After you have updated your database, you can redirect to the original page and reload your table. Then, the updated vote count should show up.