PHP Google Firestore | How to query by reference field?

Question

The $ref->where('reference_field', '=', 'Path/To/Referenced/Document'); does not work.

<?php

namespace Google\Cloud\Samples\Firestore;

use Google\Cloud\Firestore\FirestoreClient;

function query_by_reference_field($projectId)
{
    // Create the Cloud Firestore client
    $db = new FirestoreClient([
        'projectId' => $projectId,
    ]);

    $ref = $db->collection('CollectionName');
    $query = $ref->where('reference_field', '=', 'Path/To/Referenced/Document');
    $snapshot = $query->documents();
    foreach ($snapshot as $document) {
        printf('Document %s returned.' . PHP_EOL, $document->id());
    }
}

So, how do I get results where a reference field contains a given document path / document id?

@RiggsFolly Yes, I am using the framework. I have just edited my question adding a link to a full code query example. — Francisco Luz, Jan 01 '21 at 16:22
Did you spot that you have no underscore in `'reference field'` — RiggsFolly, Jan 01 '21 at 16:41
@RiggsFolly I have it figured out. I have just answered my own question. Thank you for your time and sorry if I came by sounding a bit rude. — Francisco Luz, Jan 01 '21 at 17:07

Francisco Luz · Accepted Answer · 2021-01-01T17:12:52.060

I have just figured it out by looking at this javascript question here.

The answer is: You have to pass a document reference object instead of a path string.

<?php

namespace Google\Cloud\Samples\Firestore;

use Google\Cloud\Firestore\FirestoreClient;

function query_by_reference_field($projectId)
{
    // Create the Cloud Firestore client
    $db = new FirestoreClient([
        'projectId' => $projectId,
    ]);
    
    $referenced_document = $db->document('Path/To/Referenced/Document');

    $ref = $db->collection('CollectionName');
    $query = $ref->where('reference_field', '=', $referenced_document);
    $snapshot = $query->documents();
    foreach ($snapshot as $document) {
        printf('Document %s returned.' . PHP_EOL, $document->id());
    }
}

PHP Google Firestore | How to query by reference field?

1 Answers1