Errors: Invalid argument supplied for foreach() AND Undefined Variable

PHP
,
1

Hello!
I’m working on an assignment using MySQL/PHP/HTML.

I have 3 tables:

products
productid INT(10) NOT NULL AUTO_INCREMENT PRIMARY KEY,
make VARCHAR(50),
model VARCHAR(50),
stock INT(10)

providers
providerid INT(10) NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(50),
email VARCHAR(100)

users
userid INT(10) NOT NULL AUTO_INCREMENT PRIMARY KEY,
fname VARCHAR(50),
lname VARCHAR(50),
email VARCHAR(100),
phone VARCHAR(10)

From there, I had to create the following files:
menu.php to hold HTML for nav bar, inserted into each page
footer.php to hold HTML for footer info, inserted into each page
products.php to display a list of all products in the database
providers.php to display a list of all providers in the database
users.php to display a list of all users in the database
index.php as my controller

Here’s a snippet of PHP from index.php to show/populate the products.php page:

/* Start PRODUCTS.PHP page load */
	if (isset($_GET['viewproducts']))
	{
		include 'database.php';
		try
		{
			$sql = 'SELECT productid, make, model, stock FROM products';
			$result = $pdo->query($sql);
		}
		catch (PDOException $e)
		{
			$error = "Error fetching products: " . $e->getMessage();
			include 'error.html.php';
			exit();
		}
		foreach ($result as $row)
		{
			$products[] = array(
				'productid' => $row['productid'],
				'make' => $row['make'],
				'model' => $row['model'],
				'stock' => $row['stock']);
		}
		include 'products.php';
		exit();
	}
/* End PRODUCTS.PHP page load */

This is what I have in products.php:

<?php include_once 'helpers.inc.php';?>
<!DOCTYPE html>
<html lang="en">
	<head>
		<title>Products</title>
		<meta charset="utf-8">
	</head>
	<body>
		<header>
			<?php include 'menu.php';?>
		</header>

		<main>
			<p>Here are all of the products in the database:</p>
				<ul>
					<?php foreach ($products as $product): ?>
					<li>
						<form action="" method="post">
							<div>
								<strong>Make: </strong><?php htmlout($product['make']);?><br>
								<strong>Model: </strong><?php htmlout($product['model']);?><br>
								<strong>On hand: </strong><?php htmlout($product['stock']);?>
							</div>
						</form>
					</li>
					<p>==========</p>
					<?php endforeach;?>
				</ul>
		</main>

		<footer>
			<?php include 'footer.inc.html.php'; ?>
		</footer>
	</body>
</html>

When I navigate to the providers.php page, this is what I see:

Here are all of the providers in the database:

Notice: Undefined variable: provArray in C:\xampp\htdocs\dashboard\tests\week7\lab\providers.php on line 16

Warning: Invalid argument supplied for foreach() in C:\xampp\htdocs\dashboard\tests\week7\lab\providers.php on line 16

It’s the same for my products.php and users.php pages.

What am I missing?

Thank you!

2

The script you postet does not contain any variable named provArray, so the error is somewhere else.

At least you could var_dump() the variables to have a look what’s in there. Maybe the variable is initialized within a condition that is not matched.

3

As above, you could use var_dump() or even echo() to trace through as the script runs.

Presuming that your first code snippet is not having problems connecting to the database, does it populate the $products array as you expect it to? If it does, is there something in helpers.inc.php that might be causing trouble? Does the $products array still exist after that include statement? If not, then there was.

Do the tables actually contain data? If not, or there is a chance that they will not, then your code will need to deal with that by checking whether each array exists before using it.

5

Hi @chorn and @droopsnoot,

I suppose it would help if I included the right snippets of code and error messages. That’s what I get for staring at it all day and posting right before bed! facepalm

When I navigate to the products page, this is what i get:

Notice: Undefined variable: products in C:\xampp\htdocs\dashboard\tests\week7\lab\products.php on line 16

Warning: Invalid argument supplied for foreach() in C:\xampp\htdocs\dashboard\tests\week7\lab\products.php on line 16

The following is all that’s in helpers.inc.php –

<?php
function html($text)
{
	return htmlspecialchars($text, ENT_QUOTES, 'UTF-8');
}

function htmlout($text)
{
	echo html($text);
}
?>

The tables all contain data.

When I first started the assignment, I didn’t have a separate page for each table (products/provider/users), and the data populated with no problem.

I just tried removing the IF statement, and my index.php populated the list of products.

When I took the next step to break it apart and add the IF statements, it broke.

if (isset($_GET['viewproducts']))
{
}

Something about the three different IF statements is making it not work…

Thank you!!

6

That suggests that the condition you are checking for is not true, and because it’s not true, it does not populate the arrays, and therefore you get the error message.

7

@chorn & @droopsnoot

I found the error! Of course, it wasn’t where I was looking.

The ‘menu.php’ file (which contains my nav bar) that I included in ‘products.php’ contained the following:

<?php include_once 'helpers.inc.php';?>
	<nav>
		<p><a href="index.php">Home</a>&emsp;
			<a href="products.php" id="viewproducts">Products</a>&emsp;
			<a href="providers.php" id="viewproviders">Providers</a>&emsp;
			<a href="users.php" id="viewusers">Users</a>
		</p>
	</nav>

The problem was that I assumed "id=“viewproducts” would work with my “if (isset($_GET[‘viewproducts’]))” statement…

I was so wrong.

I removed the id completely, and changed it to “href=”?viewproducts" and it works!

Woo-hoo!

Thanks for looking everything over and helping me out :slight_smile:

1 Like
8

Glad it’s working now. That’s always the danger of only posting part of the code - it’s good to try to narrow it down and only post relevant bits, but if the problem comes from the code you didn’t post, it’s hard to narrow it down.

1 Like
9

@droopsnoot Agreed! I was trying to decide between what I thought was relevant and oversharing by providing all of the code. Next issue I run in to, I’ll include all of it. :slight_smile:

Thanks again!

1 Like
10

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