Delete multiple rows by selecting checkboxes using PHP
I want to delete multiple rows from MYSQL database. I have created this delete.php file to select various links and delete them using checkboxes.
<html>
<head>
<title>Links Page</title>
</head>
<body>
<h2>Choose and delete selected links.</h2>
<?php
$dbc = mysqli_connect('localhost','root','admin','sample')
or die('Error connecting to MySQL server');
$query = "select * from links ORDER BY link_id";
$result = mysqli_query($dbc,$query)
or die('Error querying database');
$count=mysqli_num_rows($result);
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td><form name="form1" method="post" action="">
<table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<td bgcolor="#FFFFFF"> </td>
<td colspan="3" bgcolor="#FFFFFF"><strong>Delete multiple links</strong> </td>
</tr>
<tr>
<td align="center" bgcolor="#FFFFFF">#</td>
<td align="center" bgcolor="#FFFFFF"><strong>Link ID</strong></td>
<td align="center" bgcolor="#FFFFFF"><strong>Link Name</strong></td>
<td align="center" bgcolor="#FFFFFF"><strong>Link URL</strong></td>
</tr>
<?php
while ($row=mysqli_fetch_array($result)) {
?>
<tr>
<td align="center" bgcolor="#FFFFFF"><input name="checkbox" type="checkbox" value="<?php echo $row['link_id']; ?>"></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_id']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_name']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_url']; ?></td>
</tr>
<?php
}
?>
<tr>
<td colspan="4" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" value="Delete"></td>
</tr>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td><form name="form1" method="post" action="">
<table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<td bgcolor="#FFFFFF"> </td>
<td colspan="3" bgcolor="#FFFFFF"><strong>Delete multiple links</strong> </td>
</tr>
<tr>
<td align="center" bgcolor="#FFFFFF">#</td>
<td align="center" bgcolor="#FFFFFF"><strong>Link ID</strong></td>
<td align="center" bgcolor="#FFFFFF"><strong>Link Name</strong></td>
<td align="center" bgcolor="#FFFFFF"><strong>Link URL</strong></td>
</tr>
<?php
while ($row=mysqli_fetch_array($result)) {
?>
<tr>
<td align="center" bgcolor="#FFFFFF"><input name="checkbox" type="checkbox" value="<?php echo $row['link_id']; ?>"></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_id']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_name']; ?></td>
<td bgcolor="#FFFFFF"><?php echo $row['link_url']; ?></td>
</tr>
<?php
}
?>
<tr>
<td colspan="4" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" value="Delete"></td>
</tr>
<?php
// Check if delete button active, start this
if(isset($_POST['delete']))
{
$checkbox = $_POST['checkbox'];
for($i=0;$i<count($checkbox);$i++){
$del_id = $checkbox[$i];
$sql = "DELETE FROM links WHERE link_id='$del_id'";
$result = mysqli_query($sql);
}
// if successful redirect to delete_multiple.php
if($result){
echo "<meta http-equiv=\"refresh\" content=\"0;URL=view_links.php\">";
}
}
mysqli_close($dbc);
?>
</table>
</form>
</td>
</tr>
</table>
</body>
</html>
This doesn't seem to delete any row. My data is populated in the table. I guess the problem is with the PHP code. Please help me out here.
Solution 1:
You should treat it as an array like this,
<input name="checkbox[]" type="checkbox" value="<?php echo $row['link_id']; ?>">
Then only, you can take its count and loop it for deletion.
You also need to pass the database connection to the query.
$result = mysqli_query($dbc, $sql);
Yours did not include it:
$result = mysqli_query($sql);
Solution 2:
Use array notation like name="checkbox[]" in your input element. This will give you $_POST['checkbox'] as array. In the query you can utilize it as
$sql = "DELETE FROM links WHERE link_id in ";
$sql.= "('".implode("','",array_values($_POST['checkbox']))."')";
Thats one single query to delete them all.
Note: You need to escape the values passed in $_POST['checkbox'] with mysql_real_escape_string or similar to prevent SQL Injection.
Solution 3:
<?php $sql = "SELECT * FROM guest_book";
$res = mysql_query($sql);
if (mysql_num_rows($res)) {
$query = mysql_query("SELECT * FROM guest_book ORDER BY id");
$i=1;
while($row = mysql_fetch_assoc($query)){
?>
<input type="checkbox" name="checkboxstatus[<?php echo $i; ?>]" value="<?php echo $row['id']; ?>" />
<?php $i++; }} ?>
<input type="submit" value="Delete" name="Delete" />
if($_REQUEST['Delete'] != '')
{
if(!empty($_REQUEST['checkboxstatus'])) {
$checked_values = $_REQUEST['checkboxstatus'];
foreach($checked_values as $val) {
$sqldel = "DELETE from guest_book WHERE id = '$val'";
mysql_query($sqldel);
}
}
}