Get related entries in plugin via Entries field type

Question

I have 2 sections: Gift Cards and Merchants.

In Gift Cards, I have a entries field that is limited to the Merchants section and limited to 1 selection.

In Merchants, I have a field merchantId that is a plaintextfield.

In my plugin, I would like to return all gift cards that have a merchantId of 123. I've tried a few different ways, but all ways have either given no results or I get a 'missing index Merchant' error in the FieldServices class.

Hopefully someone here has done something similar and can point me in the right direction.

Answer 1

First, you should get all the Merchant Entries with the merchantId of 123

$criteria = craft()->elements->getCriteria(ElementType::Entry);
$criteria->section('merchants');
$criteria->merchantId = '123';

$merchants = $criteria->find();

Next, find all Gift Card entries that are related to the found merchants.

$criteria = craft()->elements->getCriteria(ElementType::Entry);
$criteria->section = 'giftCards';
$criteria->relatedTo = array(
    'targetElement' => $merchants,
    'field' => 'YOUR-ENTRIES-FIELD'
);

$gift_cards = $criteria->find();