Codeigniter: How to declare a global variable for a recursive function, and how to return it? - codeigniter

Question

I want to use recursion in a model in Codeigniter, and am baffled as to where I should declare the global variable to be used in the recursive function.
I'm trying to show a catalog of products, ordered by their geographical classification. The recursion is needed because the geographical database is a hierarchy tree, where a place can have sons, grandsons, great-grandsons etc (for example: London is the son of England, which is the son of Britain, which is the son of Europe).
At the end of the recursion, I want to return the variable $arrCatalog, which will hold all the products. So my other question is how to return that variable in the end?
Here is my code (not tested yet, because I didn't know how to handle the global variable):
class Catalogs_model extends CI_Model {
public function __construct()
{
parent::__construct();
}
function getCatalog($place_id, $prod_type)
{
$sql =
"SELECT id, heb_name, type FROM places p
INNER JOIN places_relations r ON p.id = r.son
WHERE father = ?
ORDER BY sort_name";
$query = $this->db->query($sql, $place_id);
if($query->num_rows() > 0) {
foreach ($query->result() as $place) {
$sql2 =
"SELECT code, heb_title, price, place_id FROM products
INNER JOIN products_places ON prod_code=code
WHERE place_id = ? AND prod_type = ?";
$query2 = $this->db->query($sql, $place_id, $prod_type);
if($query2->num_rows() > 0) {
foreach ($query2->result() as $product) {
$arrCatalog[] = $product; // $arrCatalog is the global variable I don't know where to declare and how to return.
}
$this->getCatalog($place['id'], $prod_type);
}
}
}
}
}

Answer 1

Pass your variable to the current object ($this), then you can pass it around your model or hand it to a controller.
class Catalogs_model extends CI_Model {
public $arrCatalog = array();
public function __construct() {
parent::__construct();
}
function getCatalog($place_id, $prod_type) {
$sql = "SELECT ...";
$query = $this->db->query($sql, $place_id);
if($query->num_rows() > 0) {
foreach ($query->result() as $place) {
$sql2 = "...";
$query2 = $this->db->query($sql, $place_id, $prod_type);
if($query2->num_rows() > 0) {
foreach ($query2->result() as $product) {
$this->arrCatalog[] = $product;
}
$this->getCatalog($place['id'], $prod_type);
}
}
}
}
Your controller:
$this->catalogs_model->getCatalog(2, 'hebBook');
$data['data_rows'] = $this->catalogs_model->arrCatalog;
Testing, alter your model like so ....
class Catalogs_model extends CI_Model {
public $arrCatalog = array();
// add these variables for testing ....
private $greeting = 'Hello'; // notice this is private? You cannot access this from your controller but you can from anywhere within the Catalogs_model class.
public $output = ''; // public
public $string = null; // public
// your existing code ...
function hello ()
{
$this->output = $this->greeting;
}
function hello_string ()
{
if($this->string)
{
$this->output = $this->greeting.' '.$string;
}
}
} // end class
Now test in your controller
$this->catalogs_model->hello(); // runs the hello function which sets the model->output
echo $this->catalogs_model->output; // echos 'Hello'
echo '<br />'; // just so the output stands apart in your browser.
$this->catalogs_model->string = 'World!';
$this->catalogs_model->hello_string();
echo $this->catalogs_model->output; // echos Hello World!