Edit many-to-many relationship with checkbox

[php2014]

Hello all,

 

I'm working on a project where I have 3 tables :

- test

- category

- link_category_test

 

In test I have columns id, name. In category I have the columns id, name. In link_test_category I have columns test_id, category_id.

 

When I add an item to table test I can select which categories it will belong too. It can be multiple categories. The connection between those 2 tables is stored in link_test_category. That I get to work. But now I want to be able to edit the categories connected with an item, with checkboxes. This means I'll have a list of all categories and for the categories which are connected with the item, the checkboxes are checked. The rest is unchecked. As soon as I check them they should be added to the many to many relationship table link_test_category, if they are unchecked and before where checked I want them deleted. I have the following code for creating a new item :

 

 

new.php

 

<form method="post" action="new_add.php">

<table><tr><td>

<input name="name" id="name">

</td></tr></table>

 

<table>

<?php

$query=mysqli_query($conn, "select * from category") or die (mysqli_error($conn));

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

   $category_id=$row[íd];

?>

<tr>

<td><input name="selector[]" type="checkbox" value="<php echo $category_id; ?>"></td>

<td><?php echo $row['name'] ?></td>

</tr>
<?php } ?>

</table>

 

<input name="save" type="submit" id="save">

</form>

 

 

 

new_add.php

 

<?php

$name = $_POST['name'];

 

sql = "INSERT INTO test (id, name) VALUES (NULL, '{$name}');";

$retval = mysqli_query($conn, $sql);

if(! $retval )

{

die('Could not enter data ' . mysqli_error($conn));

}

 

$insert_id = mysqli_insert_id($conn);

 

$id=$_post['selector'];

$N = count($id);

for($i=0; $i < $N; $i++)

{

$result = mysqli_query($conn, "SELECT * FROM category where id='$id[$i]'");

while($row = mysqli_fetch_array($result))

{

$sql = "INSERT INTO link_category_test (category_id, test_id) VALUES ('{ $insert_id}', '{$row['id']}');";

$retval = mysqli_query($conn, $sql);

if(! retval )

{

die('Could not enter data '. mysqli_error($conn));

}

}

}

?>