How to access fields of documents referenced by each other in MongoDB ODM?

Question

Let's suppose I have two documents

Users and Purchases. All the purchase have a reference to a User, and Users have a field gender in it.

I want to select the products bought by male clients. So I have the gender and I want to iterate thought the purchases and define their "gender".

Something like that

public function findByGender()
{
$query =
        $this->createQueryBuilder()
        ->field(""Purchase->User->gender"")->equals('male')
        ->getQuery()
        ;

}

But of course the code between ""... "" does not work. I would like to know if it is possible, and if is, how could I do it?

Answer 1

You need to separate this query in 2 queries. First select all male users and pass these users to second query. I recommend you dehydrate the queries and select only the essential.

$users = $this->createQueryBuilder()
    ->hydrate(false)
    ->select('_id')
    ->field('gender')->equals('male')
    ->getQuery()->execute()->toArray();

$products = $this->createQueryBuilder()
    ->hydrate(false)
    ->field('user.id')->in(array_keys($users))
    ->getQuery()->execute()->toArray();