Daten abrufen

Daten abrufen

Es gibt drei Möglichkeiten, in Firestore gespeicherte Daten abzurufen. Beliebige von können diese Methoden mit Dokumenten, Dokumentensammlungen oder Ergebnisse von Suchanfragen:

• Rufen Sie eine Methode auf, um die Daten einmal abzurufen.
• Legen Sie einen Listener fest, der Ereignisse zu Datenänderungen empfangen soll.
• Firestore-Snapshot-Daten im Bulk aus einer externen Quelle laden über Daten-Bundles: Weitere Informationen finden Sie in der Dokumentation zu Sets Details.

Wenn Sie einen Listener angeben, sendet Firestore Ihrem Listener einen ersten Snapshot der Daten und anschließend jedes Mal, wenn sich das Dokument ändert, einen weiteren Snapshot.

Hinweis: Die Codebeispiele decken zwar mehrere Sprachen ab, der Erläuterungstext bezieht sich jedoch auf die Namen der Webmethoden.

Hinweise

Eine der Firestore-Kurzanleitungen beachten um eine Firestore-Datenbank zu erstellen.

Firestore initialisieren

Initialisieren Sie eine Instanz von Firestore:

Webversion 9

import { initializeApp } from "firebase/app";
import { getFirestore } from "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);


// Initialize Firestore and get a reference to the service
const db = getFirestore(app);

Ersetzen Sie FIREBASE_CONFIGURATION durch den Wert für Ihre Webanwendung. firebaseConfig

Wie Sie die Daten auch dann erhalten, wenn die Verbindung des Geräts unterbrochen wird, erfahren Sie in der Dokumentation Offlinedaten aktivieren.

Webversion 8

import firebase from "firebase/app";
import "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);


// Initialize Firestore and get a reference to the service
const db = firebase.firestore();

Ersetzen Sie FIREBASE_CONFIGURATION durch den Wert für Ihre Webanwendung. firebaseConfig

Wie Sie die Daten auch dann erhalten, wenn die Verbindung des Geräts unterbrochen wird, erfahren Sie in der Dokumentation Offlinedaten aktivieren.

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

import FirebaseCore
import FirebaseFirestore

FirebaseApp.configure()

let db = Firestore.firestore()
AppDelegate.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

@import FirebaseCore;
@import FirebaseFirestore;

// Use Firebase library to configure APIs
[FIRApp configure];
  

FIRFirestore *defaultFirestore = [FIRFirestore firestore];
AppDelegate.m

Kotlin+KTX
Android

// Access a Firestore instance from your Activity

val db = Firebase.firestore
DocSnippets.kt

Java
Android

// Access a Firestore instance from your Activity

FirebaseFirestore db = FirebaseFirestore.getInstance();
DocSnippets.java

Dart

db = FirebaseFirestore.instance;

Java

import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.FirestoreOptions;

FirestoreOptions firestoreOptions =
    FirestoreOptions.getDefaultInstance().toBuilder()
        .setProjectId(projectId)
        .setCredentials(GoogleCredentials.getApplicationDefault())
        .build();
Firestore db = firestoreOptions.getService();
Quickstart.java

Python

from google.cloud import firestore

# The `project` parameter is optional and represents which project the client
# will act on behalf of. If not supplied, the client falls back to the default
# project inferred from the environment.
db = firestore.Client(project="my-project-id")
snippets.py

Python
(Async)

from google.cloud import firestore

# The `project` parameter is optional and represents which project the client
# will act on behalf of. If not supplied, the client falls back to the default
# project inferred from the environment.
db = firestore.AsyncClient(project="my-project-id")
snippets.py

C++

// Make sure the call to `Create()` happens some time before you call Firestore::GetInstance().
App::Create();
Firestore* db = Firestore::GetInstance();
AppDelegate.mm

Node.js

const Firestore = require('@google-cloud/firestore');

const db = new Firestore({
  projectId: 'YOUR_PROJECT_ID',
  keyFilename: '/path/to/keyfile.json',
});

Go

import (
	"context"
	"flag"
	"fmt"
	"log"

	"google.golang.org/api/iterator"

	"cloud.google.com/go/firestore"
)

func createClient(ctx context.Context) *firestore.Client {
	// Sets your Google Cloud Platform project ID.
	projectID := "YOUR_PROJECT_ID"

	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}
	// Close client when done with
	// defer client.Close()
	return client
}
main.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

use Google\Cloud\Firestore\FirestoreClient;

/**
 * Initialize Cloud Firestore with default project ID.
 */
function setup_client_create(string $projectId = null)
{
    // Create the Cloud Firestore client
    if (empty($projectId)) {
        // The `projectId` parameter is optional and represents which project the
        // client will act on behalf of. If not supplied, the client falls back to
        // the default project inferred from the environment.
        $db = new FirestoreClient();
        printf('Created Cloud Firestore client with default project ID.' . PHP_EOL);
    } else {
        $db = new FirestoreClient([
            'projectId' => $projectId,
        ]);
        printf('Created Cloud Firestore client with project ID: %s' . PHP_EOL, $projectId);
    }
}

Einheit

using Firebase.Firestore;
using Firebase.Extensions;

FirebaseFirestore db = FirebaseFirestore.DefaultInstance;

C#

C#

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

FirestoreDb db = FirestoreDb.Create(project);
Console.WriteLine("Created Cloud Firestore client with project ID: {0}", project);

Ruby

require "google/cloud/firestore"

# The `project_id` parameter is optional and represents which project the
# client will act on behalf of. If not supplied, the client falls back to the
# default project inferred from the environment.
firestore = Google::Cloud::Firestore.new project_id: project_id

puts "Created Cloud Firestore client with given project ID."
quickstart.rb

Beispieldaten

Schreiben zuerst einige Daten über Städte, damit wir verschiedene Arten betrachten können, wie sie gelesen werden können:

Webversion 9

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

import { collection, doc, setDoc } from "firebase/firestore"; 

const citiesRef = collection(db, "cities");

await setDoc(doc(citiesRef, "SF"), {
    name: "San Francisco", state: "CA", country: "USA",
    capital: false, population: 860000,
    regions: ["west_coast", "norcal"] });
await setDoc(doc(citiesRef, "LA"), {
    name: "Los Angeles", state: "CA", country: "USA",
    capital: false, population: 3900000,
    regions: ["west_coast", "socal"] });
await setDoc(doc(citiesRef, "DC"), {
    name: "Washington, D.C.", state: null, country: "USA",
    capital: true, population: 680000,
    regions: ["east_coast"] });
await setDoc(doc(citiesRef, "TOK"), {
    name: "Tokyo", state: null, country: "Japan",
    capital: true, population: 9000000,
    regions: ["kanto", "honshu"] });
await setDoc(doc(citiesRef, "BJ"), {
    name: "Beijing", state: null, country: "China",
    capital: true, population: 21500000,
    regions: ["jingjinji", "hebei"] });
example_data.js

Webversion 8

Weitere Informationen zur modularen Web API, die durch Tree-Shaking optimiert werden kann, und zum Upgrade von der API mit Namensraum.

var citiesRef = db.collection("cities");

citiesRef.doc("SF").set({
    name: "San Francisco", state: "CA", country: "USA",
    capital: false, population: 860000,
    regions: ["west_coast", "norcal"] });
citiesRef.doc("LA").set({
    name: "Los Angeles", state: "CA", country: "USA",
    capital: false, population: 3900000,
    regions: ["west_coast", "socal"] });
citiesRef.doc("DC").set({
    name: "Washington, D.C.", state: null, country: "USA",
    capital: true, population: 680000,
    regions: ["east_coast"] });
citiesRef.doc("TOK").set({
    name: "Tokyo", state: null, country: "Japan",
    capital: true, population: 9000000,
    regions: ["kanto", "honshu"] });
citiesRef.doc("BJ").set({
    name: "Beijing", state: null, country: "China",
    capital: true, population: 21500000,
    regions: ["jingjinji", "hebei"] });
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

let citiesRef = db.collection("cities")

citiesRef.document("SF").setData([
  "name": "San Francisco",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 860000,
  "regions": ["west_coast", "norcal"]
])
citiesRef.document("LA").setData([
  "name": "Los Angeles",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 3900000,
  "regions": ["west_coast", "socal"]
])
citiesRef.document("DC").setData([
  "name": "Washington D.C.",
  "country": "USA",
  "capital": true,
  "population": 680000,
  "regions": ["east_coast"]
])
citiesRef.document("TOK").setData([
  "name": "Tokyo",
  "country": "Japan",
  "capital": true,
  "population": 9000000,
  "regions": ["kanto", "honshu"]
])
citiesRef.document("BJ").setData([
  "name": "Beijing",
  "country": "China",
  "capital": true,
  "population": 21500000,
  "regions": ["jingjinji", "hebei"]
])
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];
[[citiesRef documentWithPath:@"SF"] setData:@{
  @"name": @"San Francisco",
  @"state": @"CA",
  @"country": @"USA",
  @"capital": @(NO),
  @"population": @860000,
  @"regions": @[@"west_coast", @"norcal"]
}];
[[citiesRef documentWithPath:@"LA"] setData:@{
  @"name": @"Los Angeles",
  @"state": @"CA",
  @"country": @"USA",
  @"capital": @(NO),
  @"population": @3900000,
  @"regions": @[@"west_coast", @"socal"]
}];
[[citiesRef documentWithPath:@"DC"] setData:@{
  @"name": @"Washington D.C.",
  @"country": @"USA",
  @"capital": @(YES),
  @"population": @680000,
  @"regions": @[@"east_coast"]
}];
[[citiesRef documentWithPath:@"TOK"] setData:@{
  @"name": @"Tokyo",
  @"country": @"Japan",
  @"capital": @(YES),
  @"population": @9000000,
  @"regions": @[@"kanto", @"honshu"]
}];
[[citiesRef documentWithPath:@"BJ"] setData:@{
  @"name": @"Beijing",
  @"country": @"China",
  @"capital": @(YES),
  @"population": @21500000,
  @"regions": @[@"jingjinji", @"hebei"]
}];
ViewController.m

Kotlin+KTX
Android

val cities = db.collection("cities")

val data1 = hashMapOf(
    "name" to "San Francisco",
    "state" to "CA",
    "country" to "USA",
    "capital" to false,
    "population" to 860000,
    "regions" to listOf("west_coast", "norcal"),
)
cities.document("SF").set(data1)

val data2 = hashMapOf(
    "name" to "Los Angeles",
    "state" to "CA",
    "country" to "USA",
    "capital" to false,
    "population" to 3900000,
    "regions" to listOf("west_coast", "socal"),
)
cities.document("LA").set(data2)

val data3 = hashMapOf(
    "name" to "Washington D.C.",
    "state" to null,
    "country" to "USA",
    "capital" to true,
    "population" to 680000,
    "regions" to listOf("east_coast"),
)
cities.document("DC").set(data3)

val data4 = hashMapOf(
    "name" to "Tokyo",
    "state" to null,
    "country" to "Japan",
    "capital" to true,
    "population" to 9000000,
    "regions" to listOf("kanto", "honshu"),
)
cities.document("TOK").set(data4)

val data5 = hashMapOf(
    "name" to "Beijing",
    "state" to null,
    "country" to "China",
    "capital" to true,
    "population" to 21500000,
    "regions" to listOf("jingjinji", "hebei"),
)
cities.document("BJ").set(data5)
DocSnippets.kt

Java
Android

CollectionReference cities = db.collection("cities");

Map<String, Object> data1 = new HashMap<>();
data1.put("name", "San Francisco");
data1.put("state", "CA");
data1.put("country", "USA");
data1.put("capital", false);
data1.put("population", 860000);
data1.put("regions", Arrays.asList("west_coast", "norcal"));
cities.document("SF").set(data1);

Map<String, Object> data2 = new HashMap<>();
data2.put("name", "Los Angeles");
data2.put("state", "CA");
data2.put("country", "USA");
data2.put("capital", false);
data2.put("population", 3900000);
data2.put("regions", Arrays.asList("west_coast", "socal"));
cities.document("LA").set(data2);

Map<String, Object> data3 = new HashMap<>();
data3.put("name", "Washington D.C.");
data3.put("state", null);
data3.put("country", "USA");
data3.put("capital", true);
data3.put("population", 680000);
data3.put("regions", Arrays.asList("east_coast"));
cities.document("DC").set(data3);

Map<String, Object> data4 = new HashMap<>();
data4.put("name", "Tokyo");
data4.put("state", null);
data4.put("country", "Japan");
data4.put("capital", true);
data4.put("population", 9000000);
data4.put("regions", Arrays.asList("kanto", "honshu"));
cities.document("TOK").set(data4);

Map<String, Object> data5 = new HashMap<>();
data5.put("name", "Beijing");
data5.put("state", null);
data5.put("country", "China");
data5.put("capital", true);
data5.put("population", 21500000);
data5.put("regions", Arrays.asList("jingjinji", "hebei"));
cities.document("BJ").set(data5);
DocSnippets.java

Dart

final cities = db.collection("cities");
final data1 = <String, dynamic>{
  "name": "San Francisco",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 860000,
  "regions": ["west_coast", "norcal"]
};
cities.doc("SF").set(data1);

final data2 = <String, dynamic>{
  "name": "Los Angeles",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 3900000,
  "regions": ["west_coast", "socal"],
};
cities.doc("LA").set(data2);

final data3 = <String, dynamic>{
  "name": "Washington D.C.",
  "state": null,
  "country": "USA",
  "capital": true,
  "population": 680000,
  "regions": ["east_coast"]
};
cities.doc("DC").set(data3);

final data4 = <String, dynamic>{
  "name": "Tokyo",
  "state": null,
  "country": "Japan",
  "capital": true,
  "population": 9000000,
  "regions": ["kanto", "honshu"]
};
cities.doc("TOK").set(data4);

final data5 = <String, dynamic>{
  "name": "Beijing",
  "state": null,
  "country": "China",
  "capital": true,
  "population": 21500000,
  "regions": ["jingjinji", "hebei"],
};
cities.doc("BJ").set(data5);
firestore.dart

Java

CollectionReference cities = db.collection("cities");
List<ApiFuture<WriteResult>> futures = new ArrayList<>();
futures.add(
    cities
        .document("SF")
        .set(
            new City(
                "San Francisco",
                "CA",
                "USA",
                false,
                860000L,
                Arrays.asList("west_coast", "norcal"))));
futures.add(
    cities
        .document("LA")
        .set(
            new City(
                "Los Angeles",
                "CA",
                "USA",
                false,
                3900000L,
                Arrays.asList("west_coast", "socal"))));
futures.add(
    cities
        .document("DC")
        .set(
            new City(
                "Washington D.C.", null, "USA", true, 680000L, Arrays.asList("east_coast"))));
futures.add(
    cities
        .document("TOK")
        .set(
            new City(
                "Tokyo", null, "Japan", true, 9000000L, Arrays.asList("kanto", "honshu"))));
futures.add(
    cities
        .document("BJ")
        .set(
            new City(
                "Beijing",
                null,
                "China",
                true,
                21500000L,
                Arrays.asList("jingjinji", "hebei"))));
// (optional) block on operation
ApiFutures.allAsList(futures).get();
RetrieveDataSnippets.java

Python

class City:
    def __init__(self, name, state, country, capital=False, population=0, regions=[]):
        self.name = name
        self.state = state
        self.country = country
        self.capital = capital
        self.population = population
        self.regions = regions

    @staticmethod
    def from_dict(source):
        # ...

    def to_dict(self):
        # ...

    def __repr__(self):
        return f"City(\
                name={self.name}, \
                country={self.country}, \
                population={self.population}, \
                capital={self.capital}, \
                regions={self.regions}\
            )"

cities_ref = db.collection("cities")
cities_ref.document("BJ").set(
    City("Beijing", None, "China", True, 21500000, ["hebei"]).to_dict()
)
cities_ref.document("SF").set(
    City(
        "San Francisco", "CA", "USA", False, 860000, ["west_coast", "norcal"]
    ).to_dict()
)
cities_ref.document("LA").set(
    City(
        "Los Angeles", "CA", "USA", False, 3900000, ["west_coast", "socal"]
    ).to_dict()
)
cities_ref.document("DC").set(
    City("Washington D.C.", None, "USA", True, 680000, ["east_coast"]).to_dict()
)
cities_ref.document("TOK").set(
    City("Tokyo", None, "Japan", True, 9000000, ["kanto", "honshu"]).to_dict()
)
snippets.py

Python
(Async)

cities_ref = db.collection("cities")
await cities_ref.document("BJ").set(
    City("Beijing", None, "China", True, 21500000, ["hebei"]).to_dict()
)
await cities_ref.document("SF").set(
    City(
        "San Francisco", "CA", "USA", False, 860000, ["west_coast", "norcal"]
    ).to_dict()
)
await cities_ref.document("LA").set(
    City(
        "Los Angeles", "CA", "USA", False, 3900000, ["west_coast", "socal"]
    ).to_dict()
)
await cities_ref.document("DC").set(
    City("Washington D.C.", None, "USA", True, 680000, ["east_coast"]).to_dict()
)
await cities_ref.document("TOK").set(
    City("Tokyo", None, "Japan", True, 9000000, ["kanto", "honshu"]).to_dict()
)
snippets.py

C++

CollectionReference cities = db->Collection("cities");

cities.Document("SF").Set({
    {"name", FieldValue::String("San Francisco")},
    {"state", FieldValue::String("CA")},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(false)},
    {"population", FieldValue::Integer(860000)},
    {"regions", FieldValue::Array({FieldValue::String("west_coast"),
                                   FieldValue::String("norcal")})},
});

cities.Document("LA").Set({
    {"name", FieldValue::String("Los Angeles")},
    {"state", FieldValue::String("CA")},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(false)},
    {"population", FieldValue::Integer(3900000)},
    {"regions", FieldValue::Array({FieldValue::String("west_coast"),
                                   FieldValue::String("socal")})},
});

cities.Document("DC").Set({
    {"name", FieldValue::String("Washington D.C.")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(680000)},
    {"regions",
     FieldValue::Array({FieldValue::String("east_coast")})},
});

cities.Document("TOK").Set({
    {"name", FieldValue::String("Tokyo")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("Japan")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(9000000)},
    {"regions", FieldValue::Array({FieldValue::String("kanto"),
                                   FieldValue::String("honshu")})},
});

cities.Document("BJ").Set({
    {"name", FieldValue::String("Beijing")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("China")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(21500000)},
    {"regions", FieldValue::Array({FieldValue::String("jingjinji"),
                                   FieldValue::String("hebei")})},
});
snippets.cpp

Node.js

const citiesRef = db.collection('cities');

await citiesRef.doc('SF').set({
  name: 'San Francisco', state: 'CA', country: 'USA',
  capital: false, population: 860000
});
await citiesRef.doc('LA').set({
  name: 'Los Angeles', state: 'CA', country: 'USA',
  capital: false, population: 3900000
});
await citiesRef.doc('DC').set({
  name: 'Washington, D.C.', state: null, country: 'USA',
  capital: true, population: 680000
});
await citiesRef.doc('TOK').set({
  name: 'Tokyo', state: null, country: 'Japan',
  capital: true, population: 9000000
});
await citiesRef.doc('BJ').set({
  name: 'Beijing', state: null, country: 'China',
  capital: true, population: 21500000
});
index.js

Go

import (
	"context"

	"cloud.google.com/go/firestore"
)

func prepareRetrieve(ctx context.Context, client *firestore.Client) error {
	cities := []struct {
		id string
		c  City
	}{
		{id: "SF", c: City{Name: "San Francisco", State: "CA", Country: "USA", Capital: false, Population: 860000}},
		{id: "LA", c: City{Name: "Los Angeles", State: "CA", Country: "USA", Capital: false, Population: 3900000}},
		{id: "DC", c: City{Name: "Washington D.C.", Country: "USA", Capital: true, Population: 680000}},
		{id: "TOK", c: City{Name: "Tokyo", Country: "Japan", Capital: true, Population: 9000000}},
		{id: "BJ", c: City{Name: "Beijing", Country: "China", Capital: true, Population: 21500000}},
	}
	for _, c := range cities {
		_, err := client.Collection("cities").Doc(c.id).Set(ctx, c.c)
		if err != nil {
			return err
		}
	}
	return nil
}
retrieve_data_get_dataset.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$citiesRef = $db->collection('samples/php/cities');
$citiesRef->document('SF')->set([
    'name' => 'San Francisco',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 860000,
    'density' => 18000,
]);
$citiesRef->document('LA')->set([
    'name' => 'Los Angeles',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 3900000,
    'density' => 8000,
]);
$citiesRef->document('DC')->set([
    'name' => 'Washington D.C.',
    'state' => null,
    'country' => 'USA',
    'capital' => true,
    'population' => 680000,
    'density' => 11000,
]);
$citiesRef->document('TOK')->set([
    'name' => 'Tokyo',
    'state' => null,
    'country' => 'Japan',
    'capital' => true,
    'population' => 9000000,
    'density' => 16000,

]);
$citiesRef->document('BJ')->set([
    'name' => 'Beijing',
    'state' => null,
    'country' => 'China',
    'capital' => true,
    'population' => 21500000,
    'density' => 3500,
]);
printf('Added example cities data to the cities collection.' . PHP_EOL);

Einheit

CollectionReference citiesRef = db.Collection("cities");
citiesRef.Document("SF").SetAsync(new Dictionary<string, object>(){
        { "Name", "San Francisco" },
        { "State", "CA" },
        { "Country", "USA" },
        { "Capital", false },
        { "Population", 860000 }
    }).ContinueWithOnMainThread(task =>
        citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
            { "Name", "Los Angeles" },
            { "State", "CA" },
            { "Country", "USA" },
            { "Capital", false },
            { "Population", 3900000 }
        })
).ContinueWithOnMainThread(task =>
    citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
            { "Name", "Washington D.C." },
            { "State", null },
            { "Country", "USA" },
            { "Capital", true },
            { "Population", 680000 }
    })
).ContinueWithOnMainThread(task =>
    citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
            { "Name", "Tokyo" },
            { "State", null },
            { "Country", "Japan" },
            { "Capital", true },
            { "Population", 9000000 }
    })
).ContinueWithOnMainThread(task =>
    citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
            { "Name", "Beijing" },
            { "State", null },
            { "Country", "China" },
            { "Capital", true },
            { "Population", 21500000 }
    })
);

C#

CollectionReference citiesRef = db.Collection("cities");
await citiesRef.Document("SF").SetAsync(new Dictionary<string, object>(){
    { "Name", "San Francisco" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 860000 }
});
await citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
    { "Name", "Los Angeles" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 3900000 }
});
await citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
    { "Name", "Washington D.C." },
    { "State", null },
    { "Country", "USA" },
    { "Capital", true },
    { "Population", 680000 }
});
await citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
    { "Name", "Tokyo" },
    { "State", null },
    { "Country", "Japan" },
    { "Capital", true },
    { "Population", 9000000 }
});
await citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
    { "Name", "Beijing" },
    { "State", null },
    { "Country", "China" },
    { "Capital", true },
    { "Population", 21500000 }
});
Console.WriteLine("Added example cities data to the cities collection.");
Program.cs

Ruby

cities_ref = firestore.col collection_path
cities_ref.doc("SF").set(
  {
    name:       "San Francisco",
    state:      "CA",
    country:    "USA",
    capital:    false,
    population: 860_000
  }
)
cities_ref.doc("LA").set(
  {
    name:       "Los Angeles",
    state:      "CA",
    country:    "USA",
    capital:    false,
    population: 3_900_000
  }
)
cities_ref.doc("DC").set(
  {
    name:       "Washington D.C.",
    state:      nil,
    country:    "USA",
    capital:    true,
    population: 680_000
  }
)
cities_ref.doc("TOK").set(
  {
    name:       "Tokyo",
    state:      nil,
    country:    "Japan",
    capital:    true,
    population: 9_000_000
  }
)
cities_ref.doc("BJ").set(
  {
    name:       "Beijing",
    state:      nil,
    country:    "China",
    capital:    true,
    population: 21_500_000
  }
)
get_data.rb

Dokument abrufen

Das folgende Beispiel zeigt, wie der Inhalt eines einzelnen Dokuments mithilfe von get() abgerufen werden kann:

Webversion 9

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

import { doc, getDoc } from "firebase/firestore";

const docRef = doc(db, "cities", "SF");
const docSnap = await getDoc(docRef);

if (docSnap.exists()) {
  console.log("Document data:", docSnap.data());
} else {
  // docSnap.data() will be undefined in this case
  console.log("No such document!");
}
get_document.js

Webversion 8

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

var docRef = db.collection("cities").doc("SF");

docRef.get().then((doc) => {
    if (doc.exists) {
        console.log("Document data:", doc.data());
    } else {
        // doc.data() will be undefined in this case
        console.log("No such document!");
    }
}).catch((error) => {
    console.log("Error getting document:", error);
});
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

let docRef = db.collection("cities").document("SF")

do {
  let document = try await docRef.getDocument()
  if document.exists {
    let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
    print("Document data: \(dataDescription)")
  } else {
    print("Document does not exist")
  }
} catch {
  print("Error getting document: \(error)")
}
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

FIRDocumentReference *docRef =
    [[self.db collectionWithPath:@"cities"] documentWithPath:@"SF"];
[docRef getDocumentWithCompletion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
  if (snapshot.exists) {
    // Document data may be nil if the document exists but has no keys or values.
    NSLog(@"Document data: %@", snapshot.data);
  } else {
    NSLog(@"Document does not exist");
  }
}];
ViewController.m

Kotlin+KTX
Android

val docRef = db.collection("cities").document("SF")
docRef.get()
    .addOnSuccessListener { document ->
        if (document != null) {
            Log.d(TAG, "DocumentSnapshot data: ${document.data}")
        } else {
            Log.d(TAG, "No such document")
        }
    }
    .addOnFailureListener { exception ->
        Log.d(TAG, "get failed with ", exception)
    }
DocSnippets.kt

Java
Android

DocumentReference docRef = db.collection("cities").document("SF");
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            DocumentSnapshot document = task.getResult();
            if (document.exists()) {
                Log.d(TAG, "DocumentSnapshot data: " + document.getData());
            } else {
                Log.d(TAG, "No such document");
            }
        } else {
            Log.d(TAG, "get failed with ", task.getException());
        }
    }
});
DocSnippets.java

Dart

final docRef = db.collection("cities").doc("SF");
docRef.get().then(
  (DocumentSnapshot doc) {
    final data = doc.data() as Map<String, dynamic>;
    // ...
  },
  onError: (e) => print("Error getting document: $e"),
);
firestore.dart

Java

DocumentReference docRef = db.collection("cities").document("SF");
// asynchronously retrieve the document
ApiFuture<DocumentSnapshot> future = docRef.get();
// ...
// future.get() blocks on response
DocumentSnapshot document = future.get();
if (document.exists()) {
  System.out.println("Document data: " + document.getData());
} else {
  System.out.println("No such document!");
}
RetrieveDataSnippets.java

Python

doc_ref = db.collection("cities").document("SF")

doc = doc_ref.get()
if doc.exists:
    print(f"Document data: {doc.to_dict()}")
else:
    print("No such document!")
snippets.py

Python
(Async)

doc_ref = db.collection("cities").document("SF")

doc = await doc_ref.get()
if doc.exists:
    print(f"Document data: {doc.to_dict()}")
else:
    print("No such document!")
snippets.py

C++

DocumentReference doc_ref = db->Collection("cities").Document("SF");
doc_ref.Get().OnCompletion([](const Future<DocumentSnapshot>& future) {
  if (future.error() == Error::kErrorOk) {
    const DocumentSnapshot& document = *future.result();
    if (document.exists()) {
      std::cout << "DocumentSnapshot id: " << document.id() << std::endl;
    } else {
      std::cout << "no such document" << std::endl;
    }
  } else {
    std::cout << "Get failed with: " << future.error_message() << std::endl;
  }
});
snippets.cpp

Node.js

const cityRef = db.collection('cities').doc('SF');
const doc = await cityRef.get();
if (!doc.exists) {
  console.log('No such document!');
} else {
  console.log('Document data:', doc.data());
}
index.js

Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
)

func docAsMap(ctx context.Context, client *firestore.Client) (map[string]interface{}, error) {
	dsnap, err := client.Collection("cities").Doc("SF").Get(ctx)
	if err != nil {
		return nil, err
	}
	m := dsnap.Data()
	fmt.Printf("Document data: %#v\n", m)
	return m, nil
}
retrieve_data_get_as_map.go

PHP

PHP

Richten Sie die Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$docRef = $db->collection('samples/php/cities')->document('SF');
$snapshot = $docRef->snapshot();

if ($snapshot->exists()) {
    printf('Document data:' . PHP_EOL);
    print_r($snapshot->data());
} else {
    printf('Document %s does not exist!' . PHP_EOL, $snapshot->id());
}

Einheit

DocumentReference docRef = db.Collection("cities").Document("SF");
docRef.GetSnapshotAsync().ContinueWithOnMainThread(task =>
{
  DocumentSnapshot snapshot = task.Result;
  if (snapshot.Exists) {
    Debug.Log(String.Format("Document data for {0} document:", snapshot.Id));
    Dictionary<string, object> city = snapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city) {
      Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
    }
  } else {
    Debug.Log(String.Format("Document {0} does not exist!", snapshot.Id));
  }
});

C#

DocumentReference docRef = db.Collection("cities").Document("SF");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
if (snapshot.Exists)
{
    Console.WriteLine("Document data for {0} document:", snapshot.Id);
    Dictionary<string, object> city = snapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city)
    {
        Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
    }
}
else
{
    Console.WriteLine("Document {0} does not exist!", snapshot.Id);
}
Program.cs

Ruby

doc_ref  = firestore.doc "#{collection_path}/SF"
snapshot = doc_ref.get
if snapshot.exists?
  puts "#{snapshot.document_id} data: #{snapshot.data}."
else
  puts "Document #{snapshot.document_id} does not exist!"
end
get_data.rb

Hinweis: Befindet sich kein Dokument an dem Standort, auf den docRef verweist, so ist das resultierende document leer und der Aufruf von exists gibt dafür false zurück.

Quelloptionen

Bei Plattformen mit Offline-Unterstützung können Sie die Option source festlegen, um zu steuern, wie ein get-Aufruf den Offline-Cache verwendet.

Standardmäßig versucht ein get-Aufruf, den neuesten Dokument-Snapshot aus Ihrer Datenbank abzurufen. Auf Plattformen mit Offline-Unterstützung verwendet die Clientbibliothek den Offline-Cache, wenn das Netzwerk nicht verfügbar ist oder wenn für die Anfrage eine Zeitüberschreitung auftritt.

Sie können die Option source in einem get()-Aufruf angeben, um das Standardverhalten zu ändern. Sie können entweder nur aus der Datenbank abrufen und den Offline-Cache ignorieren oder nur aus dem Offline-Cache abrufen. Beispiel:

Webversion 9

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

import { doc, getDocFromCache } from "firebase/firestore";

const docRef = doc(db, "cities", "SF");

// Get a document, forcing the SDK to fetch from the offline cache.
try {
  const doc = await getDocFromCache(docRef);

  // Document was found in the cache. If no cached document exists,
  // an error will be returned to the 'catch' block below.
  console.log("Cached document data:", doc.data());
} catch (e) {
  console.log("Error getting cached document:", e);
}
get_document_options.js

Webversion 8

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

var docRef = db.collection("cities").doc("SF");

// Valid options for source are 'server', 'cache', or
// 'default'. See https://firebase.google.com/docs/reference/js/v8/firebase.firestore.GetOptions
// for more information.
var getOptions = {
    source: 'cache'
};

// Get a document, forcing the SDK to fetch from the offline cache.
docRef.get(getOptions).then((doc) => {
    // Document was found in the cache. If no cached document exists,
    // an error will be returned to the 'catch' block below.
    console.log("Cached document data:", doc.data());
}).catch((error) => {
    console.log("Error getting cached document:", error);
});
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

let docRef = db.collection("cities").document("SF")

do {
  // Force the SDK to fetch the document from the cache. Could also specify
  // FirestoreSource.server or FirestoreSource.default.
  let document = try await docRef.getDocument(source: .cache)
  if document.exists {
    let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
    print("Cached document data: \(dataDescription)")
  } else {
    print("Document does not exist in cache")
  }
} catch {
  print("Error getting document: \(error)")
}
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

FIRDocumentReference *docRef =
[[self.db collectionWithPath:@"cities"] documentWithPath:@"SF"];

// Force the SDK to fetch the document from the cache. Could also specify
// FIRFirestoreSourceServer or FIRFirestoreSourceDefault.
[docRef getDocumentWithSource:FIRFirestoreSourceCache
                   completion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
  if (snapshot != NULL) {
    // The document data was found in the cache.
    NSLog(@"Cached document data: %@", snapshot.data);
  } else {
    // The document data was not found in the cache.
    NSLog(@"Document does not exist in cache: %@", error);
  }
}];
ViewController.m

Kotlin+KTX
Android

val docRef = db.collection("cities").document("SF")

// Source can be CACHE, SERVER, or DEFAULT.
val source = Source.CACHE

// Get the document, forcing the SDK to use the offline cache
docRef.get(source).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Document found in the offline cache
        val document = task.result
        Log.d(TAG, "Cached document data: ${document?.data}")
    } else {
        Log.d(TAG, "Cached get failed: ", task.exception)
    }
}
DocSnippets.kt

Java
Android

DocumentReference docRef = db.collection("cities").document("SF");

// Source can be CACHE, SERVER, or DEFAULT.
Source source = Source.CACHE;

// Get the document, forcing the SDK to use the offline cache
docRef.get(source).addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            // Document found in the offline cache
            DocumentSnapshot document = task.getResult();
            Log.d(TAG, "Cached document data: " + document.getData());
        } else {
            Log.d(TAG, "Cached get failed: ", task.getException());
        }
    }
});
DocSnippets.java

Dart

final docRef = db.collection("cities").doc("SF");

// Source can be CACHE, SERVER, or DEFAULT.
const source = Source.cache;

docRef.get(const GetOptions(source: source)).then(
      (res) => print("Successfully completed"),
      onError: (e) => print("Error completing: $e"),
    );
firestore.dart

Java

Wird im Java SDK nicht unterstützt

Python

Wird im Python SDK nicht unterstützt

C++

DocumentReference doc_ref = db->Collection("cities").Document("SF");
Source source = Source::kCache;
doc_ref.Get(source).OnCompletion([](const Future<DocumentSnapshot>& future) {
  if (future.error() == Error::kErrorOk) {
    const DocumentSnapshot& document = *future.result();
    if (document.exists()) {
      std::cout << "Cached document id: " << document.id() << std::endl;
    } else {
    }
  } else {
    std::cout << "Cached get failed: " << future.error_message() << std::endl;
  }
});
snippets.cpp

Node.js

Wird im Node.js SDK nicht unterstützt

Go

Wird im Go SDK nicht unterstützt

PHP

Wird im PHP SDK nicht unterstützt

Unity

Wird im Unity SDK nicht unterstützt

C#

Wird im C# SDK nicht unterstützt

Ruby

Wird im Ruby SDK nicht unterstützt

Benutzerdefinierte Objekte

Im vorherigen Beispiel wurde der Inhalt des Dokuments als Karte abgerufen. In einigen Sprachen ist es jedoch häufig praktischer, einen benutzerdefinierten Objekttyp zu verwenden. Unter Daten hinzufügen haben Sie eine City-Klasse festgelegt, mit der Sie die einzelnen Städte definiert haben. Sie können Ihr Dokument wieder in ein City-Objekt umwandeln:

Wenn Sie benutzerdefinierte Objekte verwenden möchten, müssen Sie eine FirestoreDataConverter-Funktion für Ihre Klasse definieren. Beispiel:

Webversion 9

Weitere Informationen zum modularen SDK der baum-shakeable Web-Version 9 und zum Upgrade von Version 8.

class City {
    constructor (name, state, country ) {
        this.name = name;
        this.state = state;
        this.country = country;
    }
    toString() {
        return this.name + ', ' + this.state + ', ' + this.country;
    }
}

// Firestore data converter
const cityConverter = {
    toFirestore: (city) => {
        return {
            name: city.name,
            state: city.state,
            country: city.country
            };
    },
    fromFirestore: (snapshot, options) => {
        const data = snapshot.data(options);
        return new City(data.name, data.state, data.country);
    }
};
city_custom_object.js

Wenn Sie benutzerdefinierte Objekte verwenden möchten, müssen Sie eine FirestoreDataConverter-Funktion für Ihre Klasse definieren. Beispiel:

Webversion 8

Weitere Informationen zum modularen SDK der baum-shakeable Web-Version 9 und zum Upgrade von Version 8.

class City {
    constructor (name, state, country ) {
        this.name = name;
        this.state = state;
        this.country = country;
    }
    toString() {
        return this.name + ', ' + this.state + ', ' + this.country;
    }
}

// Firestore data converter
var cityConverter = {
    toFirestore: function(city) {
        return {
            name: city.name,
            state: city.state,
            country: city.country
            };
    },
    fromFirestore: function(snapshot, options){
        const data = snapshot.data(options);
        return new City(data.name, data.state, data.country);
    }
};
test.firestore.js

Rufen Sie für Ihre Lesevorgänge den Datenkonverter auf. Nach der Konvertierung können Sie auf benutzerdefinierte Objektmethoden zugreifen:

Webversion 9

Weitere Informationen zum modularen SDK der baum-shakeable Web-Version 9 und zum Upgrade von Version 8.

import { doc, getDoc} from "firebase/firestore"; 

const ref = doc(db, "cities", "LA").withConverter(cityConverter);
const docSnap = await getDoc(ref);
if (docSnap.exists()) {
  // Convert to City object
  const city = docSnap.data();
  // Use a City instance method
  console.log(city.toString());
} else {
  console.log("No such document!");
}
get_custom_object.js

Rufen Sie für Ihre Lesevorgänge den Datenkonverter auf. Nach der Konvertierung können Sie auf benutzerdefinierte Objektmethoden zugreifen:

Webversion 8

Weitere Informationen zum modularen SDK der baum-shakeable Web-Version 9 und zum Upgrade von Version 8.

db.collection("cities").doc("LA")
  .withConverter(cityConverter)
  .get().then((doc) => {
    if (doc.exists){
      // Convert to City object
      var city = doc.data();
      // Use a City instance method
      console.log(city.toString());
    } else {
      console.log("No such document!");
    }}).catch((error) => {
      console.log("Error getting document:", error);
    });
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

Damit die automatische Serialisierung von Typen in Swift unterstützt wird, muss Ihr Typ dem Codable-Protokoll entsprechen.

let docRef = db.collection("cities").document("BJ")

do {
  let city = try await docRef.getDocument(as: City.self)
  print("City: \(city)")
} catch {
  print("Error decoding city: \(error)")
}
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

In Objective-C müssen Sie dies manuell tun.

FIRDocumentReference *docRef =
[[self.db collectionWithPath:@"cities"] documentWithPath:@"BJ"];
[docRef getDocumentWithCompletion:^(FIRDocumentSnapshot *snapshot, NSError *error) {
  FSTCity *city = [[FSTCity alloc] initWithDictionary:snapshot.data];
  if (city != nil) {
    NSLog(@"City: %@", city);
  } else {
    NSLog(@"Document does not exist");
  }
}];
ViewController.m

Kotlin+KTX
Android

val docRef = db.collection("cities").document("BJ")
docRef.get().addOnSuccessListener { documentSnapshot ->
    val city = documentSnapshot.toObject<City>()
}
DocSnippets.kt

Java
Android

Wichtig: Jede benutzerdefinierte Klasse muss einen öffentlichen Konstruktor haben, der keine Argumente annimmt. Darüber hinaus muss die Klasse für jedes Attribut einen öffentlichen Getter enthalten.

DocumentReference docRef = db.collection("cities").document("BJ");
docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
        City city = documentSnapshot.toObject(City.class);
    }
});
DocSnippets.java

Dart

Wenn Sie benutzerdefinierte Objekte verwenden möchten, müssen Sie Firestore-Datenkonvertierungsfunktionen für Ihre Klasse definieren. Beispiel:

class City {
  final String? name;
  final String? state;
  final String? country;
  final bool? capital;
  final int? population;
  final List<String>? regions;

  City({
    this.name,
    this.state,
    this.country,
    this.capital,
    this.population,
    this.regions,
  });

  factory City.fromFirestore(
    DocumentSnapshot<Map<String, dynamic>> snapshot,
    SnapshotOptions? options,
  ) {
    final data = snapshot.data();
    return City(
      name: data?['name'],
      state: data?['state'],
      country: data?['country'],
      capital: data?['capital'],
      population: data?['population'],
      regions:
          data?['regions'] is Iterable ? List.from(data?['regions']) : null,
    );
  }

  Map<String, dynamic> toFirestore() {
    return {
      if (name != null) "name": name,
      if (state != null) "state": state,
      if (country != null) "country": country,
      if (capital != null) "capital": capital,
      if (population != null) "population": population,
      if (regions != null) "regions": regions,
    };
  }
}
firestore_add_data_custom_objects_snippet.dart

Erstellen Sie dann eine Dokumentreferenz mit Ihren Datenkonvertierungsfunktionen. Beliebig von Lesevorgängen, die Sie mit dieser Referenz durchführen, Ihre benutzerdefinierte Klasse:

final ref = db.collection("cities").doc("LA").withConverter(
      fromFirestore: City.fromFirestore,
      toFirestore: (City city, _) => city.toFirestore(),
    );
final docSnap = await ref.get();
final city = docSnap.data(); // Convert to City object
if (city != null) {
  print(city);
} else {
  print("No such document.");
}
firestore.dart

Java

Jede benutzerdefinierte Klasse muss einen öffentlichen Konstruktor haben, der keine Argumente annimmt. Darüber hinaus muss die Klasse für jedes Attribut einen öffentlichen Getter enthalten.

DocumentReference docRef = db.collection("cities").document("BJ");
// asynchronously retrieve the document
ApiFuture<DocumentSnapshot> future = docRef.get();
// block on response
DocumentSnapshot document = future.get();
City city = null;
if (document.exists()) {
  // convert document to POJO
  city = document.toObject(City.class);
  System.out.println(city);
} else {
  System.out.println("No such document!");
}
RetrieveDataSnippets.java

Python

doc_ref = db.collection("cities").document("BJ")

doc = doc_ref.get()
city = City.from_dict(doc.to_dict())
print(city)
snippets.py

Python
(Async)

doc_ref = db.collection("cities").document("BJ")

doc = await doc_ref.get()
city = City.from_dict(doc.to_dict())
print(city)
snippets.py

C++

// This is not yet supported.

Node.js

Node.js verwendet JavaScript-Objekte.

Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
)

func docAsEntity(ctx context.Context, client *firestore.Client) (*City, error) {
	dsnap, err := client.Collection("cities").Doc("BJ").Get(ctx)
	if err != nil {
		return nil, err
	}
	var c City
	dsnap.DataTo(&c)
	fmt.Printf("Document data: %#v\n", c)
	return &c, nil
}
retrieve_data_get_as_custom_type.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$docRef = $db->collection('samples/php/cities')->document('SF');
$snapshot = $docRef->snapshot();
$city = City::fromArray($snapshot->data());

if ($snapshot->exists()) {
    printf('Document data:' . PHP_EOL);
    print((string) $city);
} else {
    printf('Document %s does not exist!' . PHP_EOL, $snapshot->id());
}

Einheit

DocumentReference docRef = db.Collection("cities").Document("BJ");

docRef.GetSnapshotAsync().ContinueWith((task) =>
{
  var snapshot = task.Result;
  if (snapshot.Exists)
  {
    Debug.Log(String.Format("Document data for {0} document:", snapshot.Id));
    City city = snapshot.ConvertTo<City>();
    Debug.Log(String.Format("Name: {0}", city.Name));
    Debug.Log(String.Format("State: {0}", city.State));
    Debug.Log(String.Format("Country: {0}", city.Country));
    Debug.Log(String.Format("Capital: {0}", city.Capital));
    Debug.Log(String.Format("Population: {0}", city.Population));
  }
  else
  {
    Debug.Log(String.Format("Document {0} does not exist!", snapshot.Id));
  }
});

C#

DocumentReference docRef = db.Collection("cities").Document("BJ");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
if (snapshot.Exists)
{
    Console.WriteLine("Document data for {0} document:", snapshot.Id);
    City city = snapshot.ConvertTo<City>();
    Console.WriteLine("Name: {0}", city.Name);
    Console.WriteLine("State: {0}", city.State);
    Console.WriteLine("Country: {0}", city.Country);
    Console.WriteLine("Capital: {0}", city.Capital);
    Console.WriteLine("Population: {0}", city.Population);
}
else
{
    Console.WriteLine("Document {0} does not exist!", snapshot.Id);
}
Program.cs

Ruby

Gilt nicht für Ruby

Mehrere Dokumente aus einer Sammlung abrufen

Sie können auch mehrere Dokumente mit einer einzigen Anfrage abrufen, indem Sie Dokumente in einer Sammlung abfragen. Sie können beispielsweise where() verwenden, um alle Dokumente abzufragen, die eine bestimmte Bedingung erfüllen, und anschließend get() verwenden, um die Ergebnisse abzurufen:

Webversion 9

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

import { collection, query, where, getDocs } from "firebase/firestore";

const q = query(collection(db, "cities"), where("capital", "==", true));

const querySnapshot = await getDocs(q);
querySnapshot.forEach((doc) => {
  // doc.data() is never undefined for query doc snapshots
  console.log(doc.id, " => ", doc.data());
});
get_multiple.js

Webversion 8

Weitere Informationen zur modularen Web API, die durch Tree-Shaking optimiert werden kann, und zum Upgrade von der API mit Namensraum.

db.collection("cities").where("capital", "==", true)
    .get()
    .then((querySnapshot) => {
        querySnapshot.forEach((doc) => {
            // doc.data() is never undefined for query doc snapshots
            console.log(doc.id, " => ", doc.data());
        });
    })
    .catch((error) => {
        console.log("Error getting documents: ", error);
    });
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

do {
  let querySnapshot = try await db.collection("cities").whereField("capital", isEqualTo: true)
    .getDocuments()
  for document in querySnapshot.documents {
    print("\(document.documentID) => \(document.data())")
  }
} catch {
  print("Error getting documents: \(error)")
}
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

[[[self.db collectionWithPath:@"cities"] queryWhereField:@"capital" isEqualTo:@(YES)]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
      if (error != nil) {
        NSLog(@"Error getting documents: %@", error);
      } else {
        for (FIRDocumentSnapshot *document in snapshot.documents) {
          NSLog(@"%@ => %@", document.documentID, document.data);
        }
      }
    }];
ViewController.m

Kotlin+KTX
Android

db.collection("cities")
    .whereEqualTo("capital", true)
    .get()
    .addOnSuccessListener { documents ->
        for (document in documents) {
            Log.d(TAG, "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.w(TAG, "Error getting documents: ", exception)
    }
DocSnippets.kt

Java
Android

db.collection("cities")
        .whereEqualTo("capital", true)
        .get()
        .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        Log.d(TAG, document.getId() + " => " + document.getData());
                    }
                } else {
                    Log.d(TAG, "Error getting documents: ", task.getException());
                }
            }
        });
DocSnippets.java

Dart

db.collection("cities").where("capital", isEqualTo: true).get().then(
  (querySnapshot) {
    print("Successfully completed");
    for (var docSnapshot in querySnapshot.docs) {
      print('${docSnapshot.id} => ${docSnapshot.data()}');
    }
  },
  onError: (e) => print("Error completing: $e"),
);
firestore.dart

Java

// asynchronously retrieve multiple documents
ApiFuture<QuerySnapshot> future = db.collection("cities").whereEqualTo("capital", true).get();
// future.get() blocks on response
List<QueryDocumentSnapshot> documents = future.get().getDocuments();
for (DocumentSnapshot document : documents) {
  System.out.println(document.getId() + " => " + document.toObject(City.class));
}
RetrieveDataSnippets.java

Python

# Note: Use of CollectionRef stream() is prefered to get()
docs = (
    db.collection("cities")
    .where(filter=FieldFilter("capital", "==", True))
    .stream()
)

for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
snippets.py

Python
(Async)

# Note: Use of CollectionRef stream() is prefered to get()
docs = (
    db.collection("cities")
    .where(filter=FieldFilter("capital", "==", True))
    .stream()
)

async for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
snippets.py

C++

db->Collection("cities")
    .WhereEqualTo("capital", FieldValue::Boolean(true))
    .Get()
    .OnCompletion([](const Future<QuerySnapshot>& future) {
      if (future.error() == Error::kErrorOk) {
        for (const DocumentSnapshot& document :
             future.result()->documents()) {
          std::cout << document << std::endl;
        }
      } else {
        std::cout << "Error getting documents: " << future.error_message()
                  << std::endl;
      }
    });
snippets.cpp

Node.js

const citiesRef = db.collection('cities');
const snapshot = await citiesRef.where('capital', '==', true).get();
if (snapshot.empty) {
  console.log('No matching documents.');
  return;
}  

snapshot.forEach(doc => {
  console.log(doc.id, '=>', doc.data());
});
index.js

Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

func multipleDocs(ctx context.Context, client *firestore.Client) error {
	fmt.Println("All capital cities:")
	iter := client.Collection("cities").Where("capital", "==", true).Documents(ctx)
	for {
		doc, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Println(doc.Data())
	}
	return nil
}
retrieve_data_query.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$citiesRef = $db->collection('samples/php/cities');
$query = $citiesRef->where('capital', '=', true);
$documents = $query->documents();
foreach ($documents as $document) {
    if ($document->exists()) {
        printf('Document data for document %s:' . PHP_EOL, $document->id());
        print_r($document->data());
        printf(PHP_EOL);
    } else {
        printf('Document %s does not exist!' . PHP_EOL, $document->id());
    }
}

Einheit

Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
capitalQuery.GetSnapshotAsync().ContinueWithOnMainThread(task => {
  QuerySnapshot capitalQuerySnapshot = task.Result;
  foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents) {
    Debug.Log(String.Format("Document data for {0} document:", documentSnapshot.Id));
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city) {
      Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
    }

    // Newline to separate entries
    Debug.Log("");
  };
});

C#

Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
QuerySnapshot capitalQuerySnapshot = await capitalQuery.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents)
{
    Console.WriteLine("Document data for {0} document:", documentSnapshot.Id);
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city)
    {
        Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
    }
    Console.WriteLine("");
}
Program.cs

Ruby

cities_ref = firestore.col collection_path

query = cities_ref.where "capital", "=", true

query.get do |city|
  puts "#{city.document_id} data: #{city.data}."
end
get_data.rb

Standardmäßig ruft Firestore alle Dokumente, die die Abfrage erfüllen, in aufsteigender Reihenfolge nach Dokument-ID ab. Sie können aber auch die zurückgegebenen Daten sortieren und beschränken.

Alle Dokumente in einer Sammlung abrufen

Darüber hinaus können Sie alle Dokumente in einer Sammlung abrufen, indem Sie den Filter where() ganz weglassen:

Webversion 9

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

import { collection, getDocs } from "firebase/firestore";

const querySnapshot = await getDocs(collection(db, "cities"));
querySnapshot.forEach((doc) => {
  // doc.data() is never undefined for query doc snapshots
  console.log(doc.id, " => ", doc.data());
});
get_multiple_all.js

Webversion 8

Informationen zur baumrüttbaren modularen Web API und Upgrade von die Namespace-API.

db.collection("cities").get().then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
        // doc.data() is never undefined for query doc snapshots
        console.log(doc.id, " => ", doc.data());
    });
});
test.firestore.js

Swift

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

do {
  let querySnapshot = try await db.collection("cities").getDocuments()
  for document in querySnapshot.documents {
    print("\(document.documentID) => \(document.data())")
  }
} catch {
  print("Error getting documents: \(error)")
}
ViewController.swift

Objective-C

Hinweis: Dieses Produkt nicht ist auf WatchOS- und App Clip-Zielen verfügbar.

[[self.db collectionWithPath:@"cities"]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
      if (error != nil) {
        NSLog(@"Error getting documents: %@", error);
      } else {
        for (FIRDocumentSnapshot *document in snapshot.documents) {
          NSLog(@"%@ => %@", document.documentID, document.data);
        }
      }
    }];
ViewController.m

Kotlin+KTX
Android

db.collection("cities")
    .get()
    .addOnSuccessListener { result ->
        for (document in result) {
            Log.d(TAG, "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.d(TAG, "Error getting documents: ", exception)
    }
DocSnippets.kt

Java
Android

db.collection("cities")
        .get()
        .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        Log.d(TAG, document.getId() + " => " + document.getData());
                    }
                } else {
                    Log.d(TAG, "Error getting documents: ", task.getException());
                }
            }
        });
DocSnippets.java

Dart

db.collection("cities").get().then(
  (querySnapshot) {
    print("Successfully completed");
    for (var docSnapshot in querySnapshot.docs) {
      print('${docSnapshot.id} => ${docSnapshot.data()}');
    }
  },
  onError: (e) => print("Error completing: $e"),
);
firestore.dart

Java

// asynchronously retrieve all documents
ApiFuture<QuerySnapshot> future = db.collection("cities").get();
// future.get() blocks on response
List<QueryDocumentSnapshot> documents = future.get().getDocuments();
for (QueryDocumentSnapshot document : documents) {
  System.out.println(document.getId() + " => " + document.toObject(City.class));
}
RetrieveDataSnippets.java

Python

docs = db.collection("cities").stream()

for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
snippets.py

Python
(Async)

docs = db.collection("cities").stream()

async for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
snippets.py

C++

db->Collection("cities").Get().OnCompletion(
    [](const Future<QuerySnapshot>& future) {
      if (future.error() == Error::kErrorOk) {
        for (const DocumentSnapshot& document :
             future.result()->documents()) {
          std::cout << document << std::endl;
        }
      } else {
        std::cout << "Error getting documents: " << future.error_message()
                  << std::endl;
      }
    });
snippets.cpp

Node.js

const citiesRef = db.collection('cities');
const snapshot = await citiesRef.get();
snapshot.forEach(doc => {
  console.log(doc.id, '=>', doc.data());
});
index.js

Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

func allDocs(ctx context.Context, client *firestore.Client) error {
	fmt.Println("All cities:")
	iter := client.Collection("cities").Documents(ctx)
	defer iter.Stop()
	for {
		doc, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Println(doc.Data())
	}
	return nil
}
retrieve_data_get_all_documents.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$citiesRef = $db->collection('samples/php/cities');
$documents = $citiesRef->documents();
foreach ($documents as $document) {
    if ($document->exists()) {
        printf('Document data for document %s:' . PHP_EOL, $document->id());
        print_r($document->data());
        printf(PHP_EOL);
    } else {
        printf('Document %s does not exist!' . PHP_EOL, $document->id());
    }
}

Einheit

Query allCitiesQuery = db.Collection("cities");
allCitiesQuery.GetSnapshotAsync().ContinueWithOnMainThread(task =>
{
  QuerySnapshot allCitiesQuerySnapshot = task.Result;
  foreach (DocumentSnapshot documentSnapshot in allCitiesQuerySnapshot.Documents)
  {
    Debug.Log(String.Format("Document data for {0} document:", documentSnapshot.Id));
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city)
    {
      Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
    }

    // Newline to separate entries
    Debug.Log("");
  }
});

C#

Query allCitiesQuery = db.Collection("cities");
QuerySnapshot allCitiesQuerySnapshot = await allCitiesQuery.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in allCitiesQuerySnapshot.Documents)
{
    Console.WriteLine("Document data for {0} document:", documentSnapshot.Id);
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city)
    {
        Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
    }
    Console.WriteLine("");
}
Program.cs

Ruby

cities_ref = firestore.col collection_path
cities_ref.get do |city|
  puts "#{city.document_id} data: #{city.data}."
end
get_data.rb

Alle Dokumente in einer untergeordneten Sammlung abrufen

Um alle Dokumente aus einer untergeordneten Sammlung abzurufen, erstellen Sie eine Referenz mit dem vollständigen Pfad zu dieser untergeordneten Sammlung:

Webversion 9

Weitere Informationen zum modularen SDK der baum-shakeable Web-Version 9 und zum Upgrade von Version 8.

const { collection, getDocs } = require("firebase/firestore");
// Query a reference to a subcollection
const querySnapshot = await getDocs(collection(db, "cities", "SF", "landmarks"));
querySnapshot.forEach((doc) => {
  // doc.data() is never undefined for query doc snapshots
  console.log(doc.id, " => ", doc.data());
});
test.firestore.js

Webversion 8

// Snippet not available

Swift

do {
  let querySnapshot = try await db.collection("cities/SF/landmarks").getDocuments()
  for document in querySnapshot.documents {
    print("\(document.documentID) => \(document.data())")
  }
} catch {
  print("Error getting documents: \(error)")
}
ViewController.swift

Objective-C

[[self.db collectionWithPath:@"cities/SF/landmarks"]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
      if (error != nil) {
        NSLog(@"Error getting documents: %@", error);
      } else {
        for (FIRDocumentSnapshot *document in snapshot.documents) {
          NSLog(@"%@ => %@", document.documentID, document.data);
        }
      }
    }];
ViewController.m

Kotlin+KTX
Android

db.collection("cities")
    .document("SF")
    .collection("landmarks")
    .get()
    .addOnSuccessListener { result ->
        for (document in result) {
            Log.d(TAG, "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.d(TAG, "Error getting documents: ", exception)
    }
DocSnippets.kt

Java
Android

db.collection("cities")
        .document("SF")
        .collection("landmarks")
        .get()
        .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        Log.d(TAG, document.getId() + " => " + document.getData());
                    }
                } else {
                    Log.d(TAG, "Error getting documents: ", task.getException());
                }
            }
        });
DocSnippets.java

Dart

db.collection("cities").doc("SF").collection("landmarks").get().then(
  (querySnapshot) {
    print("Successfully completed");
    for (var docSnapshot in querySnapshot.docs) {
      print('${docSnapshot.id} => ${docSnapshot.data()}');
    }
  },
  onError: (e) => print("Error completing: $e"),
);
firestore.dart

Java

// Snippet not available

Python

// Snippet not available

Python
(Async)

// Snippet not available

C++

// Snippet not available

Node.js

// Snippet not available

Go

// Snippet not available

PHP

// Snippet not available

Unity

// Snippet not available

C#

// Snippet not available

Ruby

// Snippet not available

Mehrere Dokumente aus einer Sammlungsgruppe abrufen

Eine Sammlungsgruppe umfasst alle Sammlungen mit derselben ID. Wenn beispielsweise jedes Dokument in Ihrer Sammlung cities eine Untersammlung namens landmarks hat, gehören all diese landmarks-Untersammlungen zur selben Sammlungsgruppe. Standardmäßig rufen Abfragen Ergebnisse aus einer einzelnen Sammlung in Ihrer Datenbank ab. Verwenden Sie eine Sammlungsgruppenabfrage, um Ergebnisse aus einer Sammlungsgruppe abzurufen, statt aus einer einzelnen Sammlung.

Untersammlungen eines Dokuments auflisten

Die Methode listCollections() der Firestore-Server-Clientbibliotheken listet alle Untersammlungen einer Dokumentenreferenz auf.

Das Abrufen einer Liste von Sammlungen ist mit den Mobil-/Web-Clientbibliotheken nicht möglich. Sie sollten nach Sammlungsnamen nur im Rahmen von Verwaltungsaufgaben in vertrauenswürdigen Serverumgebungen suchen. Wenn Sie diese Funktion in den Mobil-/Web-Clientbibliotheken benötigen, sollten Sie Ihre Daten so umstrukturieren, dass die Namen der Untersammlungen vorhersehbar sind.

Web

Nicht verfügbar in der Web-Clientbibliothek

Swift

Nicht verfügbar in der Swift-Clientbibliothek.

Objective-C

Nicht verfügbar in der Objective-C-Clientbibliothek

Kotlin+KTX
Android

Nicht verfügbar in der Android-Clientbibliothek

Java
Android

Nicht verfügbar in der Android-Clientbibliothek

Dart

Nicht verfügbar in der Flutter-Clientbibliothek.

Java

Iterable<CollectionReference> collections =
    db.collection("cities").document("SF").listCollections();

for (CollectionReference collRef : collections) {
  System.out.println("Found subcollection with id: " + collRef.getId());
}
RetrieveDataSnippets.java

Python

city_ref = db.collection("cities").document("SF")
collections = city_ref.collections()
for collection in collections:
    for doc in collection.stream():
        print(f"{doc.id} => {doc.to_dict()}")
snippets.py

Python
(Async)

collections = db.collection("cities").document("SF").collections()
async for collection in collections:
    async for doc in collection.stream():
        print(f"{doc.id} => {doc.to_dict()}")
snippets.py

C++

Nicht verfügbar in der C++-Clientbibliothek

Node.js

const sfRef = db.collection('cities').doc('SF');
const collections = await sfRef.listCollections();
collections.forEach(collection => {
  console.log('Found subcollection with id:', collection.id);
});
index.js

Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

func getCollections(ctx context.Context, client *firestore.Client) error {
	iter := client.Collection("cities").Doc("SF").Collections(ctx)
	for {
		collRef, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Printf("Found collection with id: %s\n", collRef.ID)
	}
	return nil
}
retrieve_data_get_sub_collections.go

PHP

PHP

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Firestore zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

$cityRef = $db->collection('samples/php/cities')->document('SF');
$collections = $cityRef->collections();
foreach ($collections as $collection) {
    printf('Found subcollection with id: %s' . PHP_EOL, $collection->id());
}

Einheit

// This is not yet supported in the Unity SDK.

C#

DocumentReference cityRef = db.Collection("cities").Document("SF");
IAsyncEnumerable<CollectionReference> subcollections = cityRef.ListCollectionsAsync();
IAsyncEnumerator<CollectionReference> subcollectionsEnumerator = subcollections.GetAsyncEnumerator(default);
while (await subcollectionsEnumerator.MoveNextAsync())
{
    CollectionReference subcollectionRef = subcollectionsEnumerator.Current;
    Console.WriteLine("Found subcollection with ID: {0}", subcollectionRef.Id);
}
Program.cs

Ruby

city_ref = firestore.doc "#{collection_path}/SF"
city_ref.cols do |col|
  puts col.collection_id
end
get_data.rb

Weitere Informationen zu verschiedenen Arten von Abfragen

Weitere Informationen zu Fehlercodes und zum Beheben von Latenzproblemen beim Abrufen von Daten finden Sie auf der Seite zur Fehlerbehebung.