Getting linked data from multiple tables into seperate bootstrap cards - php

Question

I very recently (as in, this week) started learning PHP and am doing a practice task.
(Therefore, apologies in advance, if I sound like I don't know what I'm talking about, that is true)
Here is a crude schematic of my tables:
I have a main table products, and there are 3 planned product types (book, disc, furniture), and each type has a special attribute, with their own tables. (size for discs, weight for books etc.)
So far through testing, I've managed to query out the object from my products table each into their separate bootstrap card components. What I am trying to accomplish now is to add the special attributes to their respective object cards.
This is where i've reached a dead end. The idea I have is to first create a seperate array $printtocard, then call all the products table records by type, then run a foreach through all the found records, and then run a switch inside the foreach where i check the product types and run cases based on type, which create new objects based on the linked table data, and add each of them to the $printtocard array.
Afterwards the plan is to call the array in the code that later outputs the objects.
Here is my code so far:
Main php code
class products {
var $arrayy;
var $sql;
var $typepr;
protected function get_prod($conn1){
$printtocard = array();
$call_type = 'SELECT type FROM products ORDER BY id';
$type_res = mysqli_query($conn1, $call_type);
$type_arr = mysqli_fetch_all($type_res, MYSQLI_ASSOC);
$this->typepr = $type_arr;
return $this->typepr;
foreach($typepr as $xxx){
switch($xxx){
case "disc":
/* $disc_ */$sql = 'SELECT p.sku, p.name, p.price, a.value FROM products AS p INNER JOIN attr_size AS a ON p.id = a.product_id;';
$val_res = mysqli_query($conn1, $sql);
$val_arr = mysqli_fetch_all($val_res, MYSQLI_ASSOC);
$printtocard[] = $val_arr;
return $this->printtocard;
break;
case "book":
/* $book_ */$sql = 'SELECT p.sku, p.name, p.price, a.value FROM products AS p INNER JOIN attr_weight AS a ON p.id = a.product_id;';
$val_res = mysqli_query($conn1, $sql);
$val_arr = mysqli_fetch_all($val_res, MYSQLI_ASSOC);
$printtocard[] = $val_arr;
return $this->printtocard;
break;
case "furniture":
/* $furniture_ */$sql = 'SELECT p.sku, p.name, p.price, a.height, a.width, a.length, FROM products AS p INNER JOIN attr_dims AS a ON p.id = a.product_id';
$val_res = mysqli_query($conn1, $sql);
$val_arr = mysqli_fetch_all($val_res, MYSQLI_ASSOC);
$printtocard[] = $val_arr;
return $this->printtocard;
break;
}
}
//$sql = 'SELECT p.sku, p.name, p.price, a.value FROM products AS p INNER JOIN attr_size AS a ON p.id = a.product_id;';
//$call2 = 'SELECT sku, name, price FROM products ORDER BY id';
//$val_res = mysqli_query($conn1, $sql);
//$val_arr = mysqli_fetch_all($val_res, MYSQLI_ASSOC);
$this->arrayy = $printtocard;
return $this->arrayy;
}
public function get_prod2($conn1)
{
$this->get_prod($conn1);
}
}
$fff= new products;
$fff->get_prod2($conn);
$sss= $fff->arrayy;
Snippet of the webpage code where I autogenerate the cards:
<div class="container">
<div class="row">
<?php
foreach($sss as $value){ ?>
<div class="col s6 md2">
<div class="card cardstyle z-depth-0">
<div class="card-content center">
<?php echo htmlspecialchars($value['sku']); ?>
<div>
<?php echo htmlspecialchars($value['name']); ?>
</div>
<div>
<?php echo htmlspecialchars($value['price']); ?>
</div>
<div>
<?php echo htmlspecialchars($value['value']); ?>
</div>
</div>
<div class="card-action right-align">
<a class="brand-text" href="#"> more info </a>
</div>
</div>
</div>
<?php } ?>
</div>
</div>
The error message I currently get:
Warning
: Invalid argument supplied for foreach() in
C:\xampp\htdocs\uzdevumi\scandi_uzdevumi_kristianskonters\productlist\productlist.php
on line
108

Answer 1

A number of pointers
1. Its better to define your variables at the top depending on your intentions later (protected, private or public)
protected $arrayy;
protected $sql;
protected $typepr;
The return just before your "foreach" loop renders your loop pointless because it stops your function there and returns what you have.
return $this->typepr;
In connection to my previous point, you seem to think that "return" does some concatenation for you as shown by each "case" you have in your switch. No it does not it exits your function back to the calling scope.
return $this->printtocard;
The warning you have at the end means what it says, you are providing the "foreach" loop with an invalid argument. In other words it does not exist, thankfully its php (dynamically typed). But the problem is its undefined (has not value). Maybe its a typo and you wanted to loop through the array variable you got from sql calls.
foreach($typepr as $xxx)
Cross check typos and I did not get to check your html.