How to use key number as a value at the array?

I have an array, where every item has a few parameters. One of the parameters is a hyperlink with the ID of that item. And I need that ID to be a key for that item value.

I've already tried something like this:

function item_preview($database)
 {
    foreach($database as $key=> $value)
    {
      $one= $key;
    }
      return $one;
}

$database= [
[
    'name'=> 'item_one',
    'img_src'=> 'pictures/item_one.jpg',
    'preview_href'=> 'item_site.php?id='.item_preview($database).'',
    'description'=> 'This product is.....' ,
],
[
    'name'=> 'item_two',
    'img_src'=> 'pictures/item_two.jpg',
    'preview_href'=> 'item_site.php?id='.item_preview($database).'',
    'description'=> 'This product is.....' ,
],
];

and what i need is...

 $database= [
 [
    'name'=> 'item_one',
    'img_src'=> 'pictures/item_one.jpg',
    'preview_href'=> 'item_site.php?id= here should be key number',
    'description'=> 'This product is.....' ,
],
[
    'name'=> 'item_two',
    'img_src'=> 'pictures/item_two.jpg',
    'preview_href'=> 'item_site.php?id= here should be key number',
    'description'=> 'This product is.....' ,
],
];

So I need id to be key of that item. So first item id=0; second item id=1;....

Solution

You could do something like

$startingIndex = 0;

$database= [
[
    'name'=> 'item_one',
    'img_src'=> 'pictures/item_one.jpg',
    'preview_href'=> 'item_site.php?id='.$startingIndex++.'',
    'description'=> 'This product is.....' ,
],
[
    'name'=> 'item_two',
    'img_src'=> 'pictures/item_two.jpg',
    'preview_href'=> 'item_site.php?id='.$startingIndex++.'',
    'description'=> 'This product is.....' ,
],

That would result in id being 0 for the first entry, 1 for the second, and so on.