subcollections.md

Working with Subcollections

The Cloud Firestore ODM is currently in alpha. Expect breaking changes, API changes and more. The documentation is still a work in progress. See the discussion for more details.

The ODM provides support for subcollections via the Collection annotation. For example, first define the root collection as normal:

@firestoreSerializable
class User {
 // ...
}

@Collection<User>('users')
final usersRef = UserCollectionReference();

Let's assume each user document contains a subcollection containing user addresses. Firstly define the model for an address:

@firestoreSerializable
class Address {
 // ...
}

Next, define the path to the subcollection in a new Collection annotation:

@Collection<User>('users')
@Collection<Address>('users/*/addresses')
final usersRef = UserCollectionReference();

After code generation, we can now access the sub-collection via the usersRef reference:

AddressCollectionReference addressesRef = usersRef.doc('myDocumentID').addresses;

The subcollection reference has full access to the same functionality as root collections. To learn more about usage of references, see the using references documentation.