creating dynamic variables in php to update multiple rows in MYSQL - php

Question

I am currently working on an update profile section of a website I am creating for fun. In this part of the update profile business owners can update their restaurant menu (menu consists of category (appetizers, entrees, etc), menu item and allergens).
Right now the website is printing out what the business owner has previously submitted in input box format, this way business owners can simply just erase and re-enter their new information. However, we don't know exactly how many menu items each restaurant has so I devised a system to dynamically update each item being altered row by row.
<?php
$sql="SELECT * from menu_item as m, allergen as a WHERE a.restaurant_id=m.restaurant_id AND m.menu_item_id=a.menu_item_id AND m.restaurant_id='".$rest_id."'";
$result11=mysqli_query($con,$sql);
if (mysqli_num_rows($result)==0){
echo "<strong>You have not submitted any menu information</strong><br><br>";
echo "Please enter your menu information here: ";
echo 'Create Menu';
}
else{
$i=0;
echo "<table border='1' cellpadding='10'><tr><th>Category</th><th>Menu Item</th><th>Allergen</th></tr>";
while($rows=mysqli_fetch_assoc($result11)) {
echo '<tr><td><input type="text" name="category'.$i.'"value="'. $rows['category']. '"</td><br>';
echo '<td><input type="text" name="menu_item'.$i.'" value="'. $rows['menu_item']. '"</td><br>';
echo '<td><input type="text" name="allergen'.$i.'" value="'. $rows['allergen']. '"</td><br>';
echo '<td><input type="hidden" name="id'.$i.'" value="'. $rows['menu_item_id']. '"</td></tr><br>';
$i++;
}
}
echo "</table>";
var_dump(mysqli_num_rows($result11));
// var_dump($_POST);
$count=0;
while ($count<=mysqli_num_rows($result11)){
${"category".$count}=mysqli_real_escape_string($con, $_POST['category'.'$count']);
$count++;
}
var_dump($category0);
?>
This is where the while loop near the bottom comes into play. I want to be able to dynamically create variables for category, menu item, and allergen. Then I want to be able to create $result variables within this same while loop (mysqli_query) and then update rows accordingly. However, right now my very last var_dump is returning a value of "" which tells me I'm either concatenating the html name attribute wrong(first while loop) or there is something wrong with concatenation in my last while loop. Does anyone know what I'm doing wrong?

Answer 1

$_POST['category'.'$count'] in your second loop should be $_POST['category'.$count]. You also only want to run this code after the form has been submitted (I'm assuming the code you've posted is not your full script so it's not clear if that's what is happening) - otherwise you'll get the original values rather than any changes the user has made in the form.
In general you'll have an easier time if you can get the submitted data into a multi-dimensional array which you can loop through, instead of having to dynamically create variables. See the section "How do I create arrays in a HTML form?" on http://php.net/manual/en/faq.html.php. In your case I'd do something like:
// (in your first while loop)
echo '<input type="text" name="menu['.$i.'][category]" value="'. htmlspecialchars($rows['category']). '"><br>';
echo '<input type="text" name="menu['.$i.'][menu_item]" value="'. htmlspecialchars($rows['menu_item']). '"><br>';
// (etc.)
You then loop through this with something like:
foreach ($_POST['menu'] as $menuRow) {
// you now have:
// $menuRow['category']
// $menuRow['menu_item']
// ...and so on
}
You also want to escape the input values you are outputting with htmlspecialchars() as I have above.