教义ODM：获取特定字段的数组

Question

So, the problem is to get ids (or any another fields) in one array, like:

[
    "someId1",
    "someId2",
    "someId3",
]

I tried to take it by next query:

$this->createQueryBuilder()
        ->select('_id')
        ->hydrate(false)
        ->getQuery()
        ->toArray()

but I took not what I want, but near this:

112 => array:1 [
  "_id" => 112
]
113 => array:1 [
  "_id" => 113
]
114 => array:1 [
  "_id" => 114
]

(I use strategy INCREMENT). I tried do this by map, reduce, but I understood that I know nothing in these functions :). So can somebody help me?

PS: I know how to realise this with php functions, like array_keys | array_values array_keys | array_values . But I really want to know how to do it by mongoDB, and particularly, in ODM with createQueryBuilder

Answer 1

This usually can be done by creating a custom hydrator. You could take a look at this example and try to adapt it to ODM https://gist.github.com/Tom32i/7984541