From where do i pass id to delete a record?

Question

Hello,

How do i pass id to delete record in this code?

<form action="index.php">
        <?php
                     mysql_connect('localhost', 'root', '');
            mysql_select_db('user');
            $query = mysql_query("Select * from tbluser");
            echo "<center>";
            echo '<table style="border:solid 2px black;">';
            while(($row = mysql_fetch_array($query)) != NULL) {
                echo '<tr>';
                echo '<td>' . $row['UserName'] . '</td>';
                echo '<td>' . $row['Password'] . '</td>';
                echo '<td>' . $row['EmailAddress'] . '</td>';
                echo '<td>' . $row['Address'] . '</td>';
                echo '<td>' . $row['Address'] . '</td>';
                echo '<td><input type = "Submit" value = "Delete" name = "btnDel" /></td>';
                echo '</tr>';
            }
            echo '</table>';
            echo "</center>";
        ?>
          </form>

The above code is in index.php and it is submitting it to itself.

Answer 1

Use this to submit the id as a part of form.

<input type="hidden" id="id" name="id" value="<? echo $row['id']; ?>" />

or you can send values in URL to do the same thing

An example:

<a href="index.php?action=delete&id=<? echo $row['id']; ?>">Delete</a>

A full working sample

<?
    mysql_connect('localhost', 'root', '');
    mysql_select_db('user');
    switch($_GET['action']) { 
        case "delete":
            $query = "DELETE FROM tbluser WHERE id='".$_GET['id']."'"
            $result = mysql_query($query);
            break;
        //well other actions
    }

    $query = mysql_query("Select * from tbluser");
    echo "<center>";
    echo '<table style="border:solid 2px black;">';
    while(($row = mysql_fetch_array($query)) != NULL) {
        echo '<tr>';
        echo '<td>' . $row['UserName'] . '</td>';
        echo '<td>' . $row['Password'] . '</td>';
        echo '<td>' . $row['EmailAddress'] . '</td>';
        echo '<td>' . $row['Address'] . '</td>';
        echo '<td>' . $row['Address'] . '</td>';
        echo '<td><a href="thispage.php?action=delete&id='.$row['id'].'">Delete</a></td>';
        echo '</tr>';
    }
    echo '</table>';
    echo "</center>";
?>

Answer 2

From the table:

echo '<input type="hidden" name="user_id" value="'.$row['id'].'" />';
echo '<td><input type = "Submit" value = "Delete" name = "btnDel" /></td>';

This will be sent to the server as a parameter named user_id. Ideally, you should be using the POST method in the form.

This assumes that the user id is named, well id in the table.

BTW, the != NULL is unnecessary.

It's sufficient to write:

while($row = mysql_fetch_array($query)) {

NULL evaluates to FALSE in a boolean context.

Update:

As mentioned in comments to another answer, there is an issue with your approach. With multiple rows, you won't be able to distinguish between user ids.

One solution would be use multiple forms.

Another option would be to have the name of the submit button include the id. You'd then parse this out of the name of the $_POST array keys.

Answer 3

You could also send it in the url at action="index.php" given that you move it below while(($row = mysql_fetch_array($query)) != NULL) { like this

echo "<form action='index.php?var=" . $row['id'] . "'>";

You would then get the variable using $_GET['var']

If the id needs to stay hidden (on the page and in the link) a hidden input element and submitting the form using method="post" like previously suggested would be the better way to go.

Answer 4

Here's how I would do it:

Change

echo '<td><input type = "Submit" value = "Delete" name = "btnDel" /></td>';

To

echo '<td><input type = "button" value = "Delete" onclick = "btnDel(' . $row['id'] . ')" /></td>';

Add the following field to the form (outside of the while loop of course):

<input type="hidden" name="id" id="userid" />

Define the following javascript function:

function btnDel(id) {
    if (confirm("Really delete id=" + id + "?")) {
        document.getElementById('userid').value = id;
        document.forms[0].submit();
    }
}​

Then you can retrieve that value using $_GET['id'] or $_POST['id'] depending on your form's method.

---

EDIT: Here's a working demo, and its source

Answer 5

Without needing javascript, seperate GET urls etc, just plain old HTML & the original POST: just add the ID to the name of the button:

<input type="submit" value="Delete" name="btnDel[<?php echo $id;?>]">

And in receiving code:

if(isset($_POST['btnDel']) && is_array($_POST['btnDel'])){
    foreach($_POST['btnDel'] as $id_to_delete => $useless_value){
        //delete item with $id_to_delete
    }
}