How to delete data from html form php mysql

Question

I'm new to php and I learned some stuffs like adding data but I got stuck in deleting data from html form. Here's my code.

database name: mydb

tablename : registered

HTML

<HTML>
<BODY>
<form method="post" action="dataout.php">
ID:<input type="Text" id="idelete" name="idelete"><br>
<input type="Submit" name="submit" value="delete">
</form>
</HTML>

dataout.php

<HTML>
<head>
</head>
<body>
<?php
$db = mysqli_connect("localhost", "root","");
mysqli_select_db($db,"mydb");
$id=$_POST['idelete'];
mysqli_query("DELETE FROM registered WHERE id=$id",$db);
echo "Information Deleted";
?>
</body>
</HTML>

When I click the button nothing appears, no errors and nothing; please help me.

Add error reporting to the top of your file(s) right after your opening PHP tag for example ` — Pedro Lobito, May 11 '15 at 02:17
When you are submitting the form, does the `idelete` field have the right ID to delete? Are the values (host, username, password and database name) inside your connection correct? — Logan Wayne, May 11 '15 at 02:41

score 3 · Accepted Answer · edited May 23 '17 at 10:26

3

This line:

mysqli_query("DELETE FROM registered WHERE id=$id",$db);

the connection comes first in mysqli_ and not last.

mysqli_query($db, "DELETE FROM registered WHERE id=$id");

http://php.net/manual/en/mysqli.query.php

mixed mysqli_query ( mysqli $link , string $query [, int $resultmode = MYSQLI_STORE_RESULT ] )

You could also do it all in one go, without using mysqli_select_db

$db = mysqli_connect("localhost", "root", "", "mydb");

You should also use conditional statements along with isset() and empty().

Also make sure the id being passed through is an int. Otherwise, you will need to quote it.

I.e.:

mysqli_query($db, "DELETE FROM registered WHERE id='$id'");

Sidenote: Your present code is open to SQL injection. Use mysqli with prepared statements, or PDO with prepared statements, they're much safer.

Make use of error reporting/checking for both PHP and MySQL.

Consult:

Edit:

Do the following:

mysqli_query($db, "DELETE FROM registered WHERE id='$id'")
  or die(mysqli_error($db));

to see if errors come of it from your query.

Add error reporting to the top of your file(s) which will help find errors.

<?php 
error_reporting(E_ALL);
ini_set('display_errors', 1);

Edit #2:

Replace:

$id=$_POST['idelete'];
mysqli_query("DELETE FROM registered WHERE id=$id",$db);

with:

if(!empty($_POST['idelete'])){
$id=$_POST['idelete'];
}
$query = "DELETE FROM registered WHERE id=$id";
$result = mysqli_query($db, $query);
if ( !$result ) {
    trigger_error('query failed', E_USER_ERROR);
}

and see if any errors come of it.

If you see "query failed...", then your query failed.
You will need to find out why.

edited May 23 '17 at 10:26

Community

1
1

answered May 11 '15 at 02:20

Funk Forty Niner

74,450
15
68
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@Emmanuel it doesn't work doesn't help me. Plus, I hope you'll be marking it as an edit under your original post. – Funk Forty Niner May 11 '15 at 02:31
im still new here im confused sorry im trying – Duckbenok May 11 '15 at 02:32
@Emmanuel if you're using your HTML form and PHP/MySQL inside the same file, you need to use a conditional statemen around the executable code. Also, do you have a webserver setup? Is the file `.php` extension? Too many things can be an issue here. – Funk Forty Niner May 11 '15 at 02:32
@Emmanuel what you did, isn't how things are done on Stack. You updated your question and overwrote everything with my code in there without marking it as an edit. I stand at getting downvoted for it, once people see the correct method and tell themselves: *"the db parameter is ok, so why the answer?"*. I have performed a rollback to the original question and you can add on to it after. – Funk Forty Niner May 11 '15 at 02:35
im sorry im really confused here – Duckbenok May 11 '15 at 02:39
@Emmanuel Reload my answer and look near the bottom under **Edit:**. there are a few ways to check for errors. Plus, since I noticed you are running under Wamp, make sure your server's properly setup and that the file is `.php` extension for the PHP/MySQL. If you made changes to your server, make sure you restarted all services and that all services are all indeed running. – Funk Forty Niner May 11 '15 at 02:39
@Emmanuel The "id" column needs to be of `int` type and not `varchar` if that is what you're using. Also, you need to make sure that whatever you enter in that input, must exist in your database. what value are you passing in that? – Funk Forty Niner May 11 '15 at 02:42
yes the id is using INT and the database is good, the wamp is also running fine – Duckbenok May 11 '15 at 02:44
@Emmanuel as I said, check for errors as outlined in my answer and make sure the `id` number you're passing in the input exists in your table and that there are no spaces anywhere, including during your input. That is about as far as I can help with this, since I can't see anything else causing problems. I too run Wamp. – Funk Forty Niner May 11 '15 at 02:50
@Emmanuel Reload my answer again, and look near the bottom again, under **Edit #2:**. If that fails, you'll need to find out why. I have to go to bed now, so I hope this gets resolved. Good luck. – Funk Forty Niner May 11 '15 at 02:59

Sunil B N · Answer 2 · 2015-05-11T02:28:00.310

0

You're misplacing db connection parameter

mysqli_query($db, "DELETE FROM registered WHERE id=$id");

edited May 11 '15 at 02:28

answered May 11 '15 at 02:26

Sunil B N

4,159
1
31
52

2

*"You're missing db connection parameter"* - it's not missing, it's misplaced – Funk Forty Niner May 11 '15 at 02:27
Correct. My answerer looks absolute wrt yours . and can't delete from phone – Sunil B N May 11 '15 at 02:29
i have updated my code but still it doesnt work. im using WAMP server and it worked before when im adding data but im having problem in deleting i just want a simple code to delete data for a beginner i would like to explore the injection thingy later – Duckbenok May 11 '15 at 02:36
Your files are in the same folder? – Sunil B N May 11 '15 at 03:05

score 0 · Answer 3 · answered May 11 '15 at 06:55

wel come to PHP

here is simple & understandable sample code

html

<form method="post" action="dataout.php">
ID:<input type="Text" id="idelete" name="idelete"><br>
<input type="Submit" name="submit" value="delete">

dataout.php file

<?php
mysql_connect("localhost", "root", "") or die("Connection Failed");  //my sql connection create
mysql_select_db("mydb")or die("Connection Failed"); // data base connection
$id = $_POST['idelete']; delete feiled id
$query = "delete from registered  where id = '".$id."'";  //query 
if(mysql_query($query)){ //check is true or false 
 echo "deleted id ".$id." ";//out put if ture
 }
 else{ 
 echo "Delete fail";//out put if false
} 
?>

i hope this will be help to improve your php https://www.siteground.com/tutorials/php-mysql/display_table_data.htm

How to delete data from html form php mysql

3 Answers3