CODEWITHSUNDEEP
fluttergoogle-cloud-firestoresnapshot
Bruno Zirnstein
Bruno Zirnstein

Reputation: 1

Basic firestore query in flutter returns empty snapshot

I tried to do a simple firestore query in flutter, however it always returns an empty snapshot. With the collection categories it already worked. The code for the products was actually only copy pasted.

import 'dart:async';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:foodandfast/services/models.dart';

class FirestoreService {
  final FirebaseFirestore _db = FirebaseFirestore.instance;

  Future<List<Category>> getCategories() async {
    var ref = _db.collection("categories");
    var snapshot = await ref.orderBy("name", descending: false).get();
    var data = snapshot.docs.map((s) {
      var element = s.data();
      element\["id"\] = s.id;
      element\["imageName"\] += ".png";
      return element;
    });
    var categories = data.map((d) => Category.fromJson(d));
    return categories.toList();
  }

  Future<List<Product>> getProducts(String categoryId) async {
    var ref = FirebaseFirestore.instance.collection("products");
    var snapshot = await ref
        .orderBy("name", descending: false)
        .where('categoryId', isEqualTo: categoryId)
        .get();
    print(snapshot.docs.length);
    var data = snapshot.docs.map((s) {
      var element = s.data();
      element\["id"\] = s.id;
      element\["imageName"\] += ".png";
      return element;
    });
    var products = data.map((d) => Product.fromJson(d));
    return products.toList();
  }
}]

Firestore database

Upvotes: 0

Views: 587

Answers (1)

Mubarak B
Mubarak B

Reputation: 60

There is no categoryId field in Products collections, thats why getProducts() returns empty.

however, firebase is noSQL database, unlike SQL you can't apply the principle of foreign key in noSQL.

you need to learn more about data modeling in noSQL database.

Upvotes: 1

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