flutter - Adding collection and subcollection data to model entity from firestore firebase

Question

I'm recently started using Firebase firestore. I'm stuck at the point were the collection have sub collections and get those items to my model.

Let say I have this collection

meats
   id : 1
   name : Chicken
 subMeats 
       id : 11
       name : Country Chicken
       id : 12
       name : Broiler Chicken
meats 
   id : 2
   name : Pork
subMeats
       id : 21  
       name : White Pork
       id : 22
       name : Black Pork

     return meatTypeCollection.get().then((value) {
  value.docs.forEach((mainDoc) {
   // MainMeatEntity.fromSnapshot(mainDoc)    
    _logger.i(mainDoc.data()['name']);
    meatTypeCollection
        .doc(mainDoc.id)
        .collection('subMeats')
        .get()
        .then((snapShots) {
      snapShots.docs.forEach((doc) {
        _logger.i(doc.data()['name']);
        MainMeat.fromEntity(MainMeatEntity.fromSnapshot(doc));
      });
    });
  });
  //return MeatTypes.fromEntity(MeatTypeEntity.fromJson(value.docs));
}).catchError((error) => _logger.e("Failed to load meat types : $error"));

The above does not capture the collection. I use entity to model.

   import 'package:flutter/cupertino.dart';
   import 'entities/main_meat_entity.dart';
   import 'entities/meat_type_entity.dart';

    @immutable
    class MainMeat {
    final String id;
    final String name;
    final MeatTypeEntity subMeats;
    final String shopId;

 const MainMeat({
   this.id,
   this.name,
   this.subMeats,
   this.shopId,
 });

 static MainMeat fromEntity(MainMeatEntity mainMeatEntity) {
   return MainMeat(
    id: mainMeatEntity.id,
    name: mainMeatEntity.name,
    subMeats: mainMeatEntity.subMeats,
    shopId: mainMeatEntity.shopId,
   );
  }

  MainMeatEntity toEntity() {
     return MainMeatEntity(id, name, subMeats, shopId);
  }

  static const empty = MainMeat(id: '', shopId: "", name: "");
   }
  -----------------------------****************--------------------
  part 'meat_type_entity.g.dart';

 @JsonSerializable()
 class MeatTypeEntity extends Equatable {
  final String id;
  final String name;
  final String shopId;

  const MeatTypeEntity(this.id, this.name, this.shopId);

  factory MeatTypeEntity.fromJson(Map<String, dynamic> json) =>
  _$MeatTypeEntityFromJson(json);

   Map<String, dynamic> toJson() => _$MeatTypeEntityToJson(this);

   @override
   List<Object> get props => [
     id,
     name,
     shopId,
    ];

   static MeatTypeEntity fromSnapshot(DocumentSnapshot snap) {
    return MeatTypeEntity(
    snap.id,
    snap.data()['name'],
    snap.data()["shopId"],
      );
     }

    Map<String, Object> toDocument() {
     return {
     "id": id,
     'mainMeat': name,
     "shopId": shopId,
     };
    }
   }

I can list it's collection and sub collections fine. But not sure to load into my model. Any help appreciated thanks.

Answer 1

You can't store subCollection to collection directly, Read FireStore data model section.

So your structure will be look like Meal(document) -> all meal collection -> Sub Meal (document) -> all sub meals collection.

If you want to read the data like firebase database, you can't read the complete tree/hierarchy at a time.