UPDATE table with checkboxes - php

Question

I have the facility to update what I call 'documents' (ver similar to creating a post) on my cms which works fine but I have introduced categories where the documents are associated to them. Now I have managed to bind them when creating the doc from new but when trying update them I am getting a bit stuck. I am using checkboxes to show the list of categories and when selected it updates a join table which uses the doc_id and the cat_id.
Here is the script for updating the doc:
<?php
include ('includes/header.php');
require ('../../db_con.php');
echo '<h1>Document Edit</h1>';
// Check for a valid document ID, through GET or POST:
if ( (isset($_GET['id'])) && (is_numeric($_GET['id'])) ) { // From view_docs.php
$id = $_GET['id'];
} elseif ( (isset($_POST['id'])) && (is_numeric($_POST['id'])) ) { // Form submission.
$id = $_POST['id'];
} else { // No valid ID, kill the script.
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}
// Check if the form has been submitted:
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
$errors = array();
// Check for a document name:
if (empty($_POST['doc_name'])) {
$errors[] = 'You forgot to enter your document name.';
} else {
$dn = mysqli_real_escape_string($dbc, trim($_POST['doc_name']));
}
// Check for a document content:
if (empty($_POST['doc_content'])) {
$errors[] = 'You forgot to enter your last name.';
} else {
$dc = mysqli_real_escape_string($dbc, trim($_POST['doc_content']));
}
if (empty($errors)) { // If everything's OK.
// Test for unique doc title:
$q = "SELECT doc_id FROM docs WHERE doc_name='$dn' AND doc_id != $id";
$r = mysqli_query($dbc, $q);
if (mysqli_num_rows($r) == 0) {
// Make the query:
$q = "UPDATE docs SET doc_name='$dn', doc_content='$dc', doc_name='$dn' WHERE doc_id=$id LIMIT 1";
$r = mysqli_query ($dbc, $q);
if (mysqli_affected_rows($dbc) == 1) { // If it ran OK.
$doc_id = mysqli_insert_id($dbc);
$query = "UPDATE doc_cat_join (cat_id,doc_id) VALUES ";
$cat_ids = $_POST['cat_id'];
$length = count($cat_ids);
for ($i = 0; $i < count($cat_ids); $i++) {
$query.='(' . $cat_ids[$i] . ',' . $doc_id . ')';
if ($i < $length - 1)
$query.=',';
}
// Print a message:
echo '<p>The document has been edited.</p>';
} else { // If it did not run OK.
echo '<p class="error">The document could not be edited due to a system error. We apologize for any inconvenience.</p>'; // Public message.
echo '<p>' . mysqli_error($dbc) . '<br />Query: ' . $q . '</p>'; // Debugging message.
}
} else { // Already used.
echo '<p class="error">The document name has already been used.</p>';
}
} else { // Report the errors.
echo '<p class="error">The following error(s) occurred:<br />';
foreach ($errors as $msg) { // Print each error.
echo " - $msg<br />\n";
}
echo '</p><p>Please try again.</p>';
} // End of if (empty($errors)) IF.
} // End of submit conditional.
// Always show the form...
// Retrieve the document's information:
$q = "SELECT * FROM docs WHERE doc_id=$id";
$r = mysqli_query ($dbc, $q);
if (mysqli_num_rows($r) == 1) { // Valid document ID, show the form.
// Get the document's information:
$row = mysqli_fetch_array ($r, MYSQLI_NUM);
// Create the form:
echo '<form action="edit_doc.php" method="post">
<p>Document Name: <input type="text" name="doc_name" size="15" maxlength="15" value="' . $row[1] . '" /></p>
<textarea name="doc_content" id="doc_content" placeholder="Document Content" style="display: none;"></textarea>
<iframe name="editor" id="editor" ></iframe>'
?>
<div class="row">
<div class="col-group-1">
<?php
$q = "SELECT * FROM cats";
$r = mysqli_query ($dbc, $q); // Run the query.
echo '<div class="view_body">';
// FETCH AND PRINT ALL THE RECORDS
while ($row = mysqli_fetch_array($r)) {
echo '<br><label><input type="checkbox" name="cat_id[]" value="' . $row['cat_id'] . '">' . $row["cat_name"] . '</label>';
}
echo '</div>';
?>
</div>
</div>
<br><br>
<input onclick="formsubmit()" type="submit" value="Update Document" name="submit"/>
<?php echo'
<input type="hidden" name="id" value="' . $id . '" />
</form>
<br><br>Back to docs list';
} else { // Not a valid document ID.
echo '<p class="error">This page has been accessed in error.</p>';
}
?>
<?php
mysqli_close($dbc);
?>
So I have three tables:
docs
doc_id
doc_name
doc_content
cats
cat_id
cat_name
doc_cat_join
doc_id
cat_id
the join table related the doc_id and cat_id which then associates them together. I am guessing in my script when I update a doc it will need to delete the rows and then re-insert them? I just need to know a way or the easiest way of updating the join table as I am a tad stuck...

Answer 1

In case of checkbox update you need to delete previous stored checkbox of with appropriate id and insert new one you can't update checkbox as we can't predict how many checkbox will be selected by user....
Case:
It may happen that user remove one checkbox at update time so you will never know which one to be deleted.......
In your code...
docs
doc_id
doc_name
doc_content
cats
cat_id
cat_name
doc_cat_join
id
doc_id
cat_id
here you have to delete old checkbox of updation doc,
DELETE FROM doc_cat_join WHERE cat_id = some_id
next you can insert selected checkbox as you are inserting first time...