Query Documents that has type reference in Firestore

Question

According to Cloud Firestore=>Data type Documentation, type reference act as foreign key in NoSQL world. but when I query it in Fluter/Dart. Database in Firestore.

[Collection]

Note: DocumentOne's data type are all reference

1. CollectionWithReference
   • DocumentOne
     • FKOne/doc001
     • FKTwo/doc002
2. FKOne
   • doc001
     • "someData": 'Just Some Data'
3. FKTwo
   • doc002
     • "anotherData": 'Just Another Data'

Example Code:

Firestore.instance.collection('CollectionWithReference').snapshots()
  .listen((data) => data.documents.forEach((document) => print(document.data)));

Output

{FKOne: Instance of 'DocumentReference', FKTwo: [Instance of 'DocumentReference', Instance of 'DocumentReference', Instance of 'DocumentReference']}

Answer 1

The output in your question is to be expected.
Because your references are parsed as objects, print will only print out Instance of 'DocumentReference'.

Here you can take a look at the class DocumentReference, which contains all the necessary data about your reference.
In the following code I will print out the path (which is a getter of every DocumentReference object) of each of your references:

Firestore.instance.collection('CollectionWithReference').snapshots().listen((data) {
  data.documents.forEach((document) {
      print(document.data['FKOne'].path);
      document.data['FKTwo'].forEach((documentReference) => print(documentReference.path));
  });
});