I'm looking for a way to prevent repeated calls to the database if the item in question has already been loaded previously. The reason is that we have a lot of different areas that show popular items, latest releases, top rated etc. and sometimes it happens that one item appears in multiple lists on the same page.
I wonder if it's possible to save the object instance in a static array associated with the class and then check if the data is actually in there yet, but then how do I point the new instance to the existing one?
Here's a draft of my idea:
$baseball = new Item($idOfTheBaseballItem);
$baseballAgain = new Item($idOfTheBaseballItem);
class Item
{
static $arrItems = array();
function __construct($id) {
if(in_array($id, self::arrItems)){
// Point this instance to the object in self::arrItems[$id]
// But how?
}
else {
// Call the database
self::arrItems[id] = $this;
}
}
}
If you have any other ideas or you just think I'm totally nuts, let me know.
You should know that static variables only exist in the page they were created, meaning 2 users that load the same page and get served the same script still exist as 2 different memory spaces.
You should consider caching results, take a look at code igniter database caching
What you are trying to achieve is similar to a singleton factory
$baseball = getItem($idOfTheBaseballItem);
$baseballAgain =getItem($idOfTheBaseballItem);
function getItem($id){
static $items=array();
if(!isset($items[$id])$items[$id]=new Item($id);
return $items[$id];
}
class Item{
// this stays the same
}
P.S. Also take a look at memcache. A very simple way to remove database load is to create a /cache/ directory and save database results there for a few minutes or until you deem the data old (this can be done in a number of ways, but most approaches are time based)
You can't directly replace "this" in constructor. Instead, prepare a static function like "getById($id)" that returns object from list. And as stated above: this will work only per page load.