Разбивка данных на страницы с помощью курсоров запросов

С помощью курсоров запросов в Cloud Firestore вы можете разделить данные, возвращаемые запросом, на пакеты в соответствии с параметрами, которые вы определяете в своем запросе.

Курсоры запросов определяют начальную и конечную точки запроса, что позволяет:

  • Вернуть подмножество данных.
  • Разбить результаты запроса на страницы.

Однако, чтобы определить определенный диапазон для запроса, вы должны использовать метод where() , описанный в разделе « Простые запросы» .

Добавить простой курсор в запрос

Используйте startAt() или startAfter() , чтобы определить начальную точку запроса. Метод startAt() включает начальную точку, а метод startAfter() исключает ее.

Например, если вы используете startAt(A) в запросе, он возвращает весь алфавит. Если вместо этого вы используете startAfter(A) , он возвращает BZ .

Web version 9

import { query, orderBy, startAt } from "firebase/firestore";  

const q = query(citiesRef, orderBy("population"), startAt(1000000));

Web version 8

citiesRef.orderBy("population").startAt(1000000);
Быстрый
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Get all cities with population over one million, ordered by population.
db.collection("cities")
    .order(by: "population")
    .start(at: [1000000])
Цель-C
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Get all cities with population over one million, ordered by population.
[[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"population"]
    queryStartingAtValues:@[ @1000000 ]];

Java

// Get all cities with a population >= 1,000,000, ordered by population,
db.collection("cities")
        .orderBy("population")
        .startAt(1000000);

Kotlin+KTX

// Get all cities with a population >= 1,000,000, ordered by population,
db.collection("cities")
        .orderBy("population")
        .startAt(1000000)

Dart

db.collection("cities").orderBy("population").startAt([1000000]);
Джава
Query query = cities.orderBy("population").startAt(4921000L);
питон
cities_ref = db.collection(u'cities')
query_start_at = cities_ref.order_by(u'population').start_at({
    u'population': 1000000
})

Python

cities_ref = db.collection("cities")
query_start_at = cities_ref.order_by("population").start_at({"population": 1000000})
С++
// Get all cities with a population >= 1,000,000, ordered by population,
db->Collection("cities")
    .OrderBy("population")
    .StartAt({FieldValue::Integer(1000000)});
Node.js
const startAtRes = await db.collection('cities')
  .orderBy('population')
  .startAt(1000000)
  .get();
Идти
query := client.Collection("cities").OrderBy("population", firestore.Asc).StartAt(1000000)
PHP
$query = $citiesRef
    ->orderBy('population')
    ->startAt([1000000]);
Единство
Query query = citiesRef.OrderBy("Population").StartAt(1000000);
С#
Query query = citiesRef.OrderBy("Population").StartAt(1000000);
Рубин
query = cities_ref.order("population").start_at(1_000_000)

Точно так же используйте endAt() или endBefore() , чтобы определить конечную точку для результатов вашего запроса.

Web version 9

import { query, orderBy, endAt } from "firebase/firestore";  

const q = query(citiesRef, orderBy("population"), endAt(1000000));

Web version 8

citiesRef.orderBy("population").endAt(1000000);
Быстрый
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Get all cities with population less than one million, ordered by population.
db.collection("cities")
    .order(by: "population")
    .end(at: [1000000])
Цель-C
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Get all cities with population less than one million, ordered by population.
[[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"population"]
    queryEndingAtValues:@[ @1000000 ]];

Java

// Get all cities with a population <= 1,000,000, ordered by population,
db.collection("cities")
        .orderBy("population")
        .endAt(1000000);

Kotlin+KTX

// Get all cities with a population <= 1,000,000, ordered by population,
db.collection("cities")
        .orderBy("population")
        .endAt(1000000)

Dart

db.collection("cities").orderBy("population").endAt([1000000]);
Джава
Query query = cities.orderBy("population").endAt(4921000L);
питон
cities_ref = db.collection(u'cities')
query_end_at = cities_ref.order_by(u'population').end_at({
    u'population': 1000000
})

Python

cities_ref = db.collection("cities")
query_end_at = cities_ref.order_by("population").end_at({"population": 1000000})
С++
// Get all cities with a population <= 1,000,000, ordered by population,
db->Collection("cities")
    .OrderBy("population")
    .EndAt({FieldValue::Integer(1000000)});
Node.js
const endAtRes = await db.collection('cities')
  .orderBy('population')
  .endAt(1000000)
  .get();
Идти
query := client.Collection("cities").OrderBy("population", firestore.Asc).EndAt(1000000)
PHP
$query = $citiesRef
    ->orderBy('population')
    ->endAt([1000000]);
Единство
Query query = citiesRef.OrderBy("Population").EndAt(1000000);
С#
Query query = citiesRef.OrderBy("Population").EndAt(1000000);
Рубин
query = cities_ref.order("population").end_at(1_000_000)

Используйте снимок документа для определения курсора запроса

Вы также можете передать моментальный снимок документа в предложение курсора в качестве начальной или конечной точки курсора запроса. Значения в моментальном снимке документа служат значениями в курсоре запроса.

Например, сделайте снимок документа «Сан-Франциско» в своем наборе данных о городах и населении. Затем используйте этот снимок документа в качестве отправной точки для курсора запроса населения. Ваш запрос вернет все города с населением, большим или равным населению Сан-Франциско, как указано в снимке документа.

Web version 9

import { collection, doc, getDoc, query, orderBy, startAt } from "firebase/firestore";  
const citiesRef = collection(db, "cities");

const docSnap = await getDoc(doc(citiesRef, "SF"));

// Get all cities with a population bigger than San Francisco
const biggerThanSf = query(citiesRef, orderBy("population"), startAt(docSnap));
// ...

Web version 8

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

return citiesRef.doc("SF").get().then((doc) => {
    // Get all cities with a population bigger than San Francisco
    var biggerThanSf = citiesRef
        .orderBy("population")
        .startAt(doc);

    // ...
});
Быстрый
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
db.collection("cities")
    .document("SF")
    .addSnapshotListener { (document, error) in
        guard let document = document else {
            print("Error retreving cities: \(error.debugDescription)")
            return
        }

        // Get all cities with a population greater than or equal to San Francisco.
        let sfSizeOrBigger = db.collection("cities")
            .order(by: "population")
            .start(atDocument: document)
}
Цель-C
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
[[[db collectionWithPath:@"cities"] documentWithPath:@"SF"]
    addSnapshotListener:^(FIRDocumentSnapshot *snapshot, NSError *error) {
      if (snapshot == nil) {
        NSLog(@"Error retreiving cities: %@", error);
        return;
      }
      // Get all cities with a population greater than or equal to San Francisco.
      FIRQuery *sfSizeOrBigger = [[[db collectionWithPath:@"cities"]
          queryOrderedByField:@"population"]
          queryStartingAtDocument:snapshot];
    }];

Java

// Get the data for "San Francisco"
db.collection("cities").document("SF")
        .get()
        .addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
            @Override
            public void onSuccess(DocumentSnapshot documentSnapshot) {
                // Get all cities with a population bigger than San Francisco.
                Query biggerThanSf = db.collection("cities")
                        .orderBy("population")
                        .startAt(documentSnapshot);

                // ...
            }
        });

Kotlin+KTX

// Get the data for "San Francisco"
db.collection("cities").document("SF")
        .get()
        .addOnSuccessListener { documentSnapshot ->
            // Get all cities with a population bigger than San Francisco.
            val biggerThanSf = db.collection("cities")
                    .orderBy("population")
                    .startAt(documentSnapshot)

            // ...
        }

Dart

db.collection("cities").doc("SF").get().then(
  (documentSnapshot) {
    final biggerThanSf = db
        .collection("cities")
        .orderBy("population")
        .startAt([documentSnapshot]);
  },
  onError: (e) => print("Error: $e"),
);
Джава
// Fetch the snapshot with an API call, waiting for a maximum of 30 seconds for a result.
ApiFuture<DocumentSnapshot> future = db.collection("cities").document("SF").get();
DocumentSnapshot snapshot = future.get(30, TimeUnit.SECONDS);

// Construct the query
Query query = db.collection("cities").orderBy("population").startAt(snapshot);
питон
doc_ref = db.collection(u'cities').document(u'SF')

snapshot = doc_ref.get()
start_at_snapshot = db.collection(
    u'cities').order_by(u'population').start_at(snapshot)

Python

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

snapshot = await doc_ref.get()
start_at_snapshot = (
    db.collection("cities").order_by("population").start_at(snapshot)
)
С++
db->Collection("cities").Document("SF").Get().OnCompletion(
    [db](const Future<DocumentSnapshot>& future) {
      if (future.error() == Error::kErrorOk) {
        const DocumentSnapshot& document_snapshot = *future.result();
        Query bigger_than_sf = db->Collection("cities")
                                   .OrderBy("population")
                                   .StartAt({document_snapshot});
        // ...
      }
    });
Node.js
const docRef = db.collection('cities').doc('SF');
const snapshot = await docRef.get();
const startAtSnapshot = db.collection('cities')
  .orderBy('population')
  .startAt(snapshot);

await startAtSnapshot.limit(10).get();
Идти
cities := client.Collection("cities")
dsnap, err := cities.Doc("SF").Get(ctx)
if err != nil {
	fmt.Println(err)
}
query := cities.OrderBy("population", firestore.Asc).StartAt(dsnap.Data()["population"]).Documents(ctx)
PHP
$citiesRef = $db->collection('samples/php/cities');
$docRef = $citiesRef->document('SF');
$snapshot = $docRef->snapshot();

$query = $citiesRef
    ->orderBy('population')
    ->startAt($snapshot);
Единство
CollectionReference citiesRef = db.Collection("cities");
DocumentReference docRef = citiesRef.Document("SF");
docRef.GetSnapshotAsync().ContinueWith((snapshotTask) =>
{
    Query query = citiesRef.OrderBy("Population").StartAt(snapshotTask.Result);
});
С#
CollectionReference citiesRef = db.Collection("cities");
DocumentReference docRef = citiesRef.Document("SF");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
Query query = citiesRef.OrderBy("Population").StartAt(snapshot);
Рубин
doc_ref = firestore.doc "#{collection_path}/SF"
snapshot = doc_ref.get
query = cities_ref.order("population").start_at(snapshot)

Разбить запрос на страницы

Разбивайте запросы на страницы, комбинируя курсоры запросов с методом limit() . Например, используйте последний документ в пакете в качестве начала курсора для следующего пакета.

Web version 9

import { collection, query, orderBy, startAfter, limit, getDocs } from "firebase/firestore";  

// Query the first page of docs
const first = query(collection(db, "cities"), orderBy("population"), limit(25));
const documentSnapshots = await getDocs(first);

// Get the last visible document
const lastVisible = documentSnapshots.docs[documentSnapshots.docs.length-1];
console.log("last", lastVisible);

// Construct a new query starting at this document,
// get the next 25 cities.
const next = query(collection(db, "cities"),
    orderBy("population"),
    startAfter(lastVisible),
    limit(25));

Web version 8

var first = db.collection("cities")
        .orderBy("population")
        .limit(25);

return first.get().then((documentSnapshots) => {
  // Get the last visible document
  var lastVisible = documentSnapshots.docs[documentSnapshots.docs.length-1];
  console.log("last", lastVisible);

  // Construct a new query starting at this document,
  // get the next 25 cities.
  var next = db.collection("cities")
          .orderBy("population")
          .startAfter(lastVisible)
          .limit(25);
});
Быстрый
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Construct query for first 25 cities, ordered by population
let first = db.collection("cities")
    .order(by: "population")
    .limit(to: 25)

first.addSnapshotListener { (snapshot, error) in
    guard let snapshot = snapshot else {
        print("Error retreving cities: \(error.debugDescription)")
        return
    }

    guard let lastSnapshot = snapshot.documents.last else {
        // The collection is empty.
        return
    }

    // Construct a new query starting after this document,
    // retrieving the next 25 cities.
    let next = db.collection("cities")
        .order(by: "population")
        .start(afterDocument: lastSnapshot)

    // Use the query for pagination.
    // ...
}
Цель-C
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
FIRQuery *first = [[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"population"]
    queryLimitedTo:25];
[first addSnapshotListener:^(FIRQuerySnapshot *snapshot, NSError *error) {
  if (snapshot == nil) {
    NSLog(@"Error retreiving cities: %@", error);
    return;
  }
  if (snapshot.documents.count == 0) { return; }
  FIRDocumentSnapshot *lastSnapshot = snapshot.documents.lastObject;

  // Construct a new query starting after this document,
  // retreiving the next 25 cities.
  FIRQuery *next = [[[db collectionWithPath:@"cities"]
      queryOrderedByField:@"population"]
      queryStartingAfterDocument:lastSnapshot];
  // Use the query for pagination.
  // ...
}];

Java

// Construct query for first 25 cities, ordered by population
Query first = db.collection("cities")
        .orderBy("population")
        .limit(25);

first.get()
    .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
        @Override
        public void onSuccess(QuerySnapshot documentSnapshots) {
            // ...

            // Get the last visible document
            DocumentSnapshot lastVisible = documentSnapshots.getDocuments()
                    .get(documentSnapshots.size() -1);

            // Construct a new query starting at this document,
            // get the next 25 cities.
            Query next = db.collection("cities")
                    .orderBy("population")
                    .startAfter(lastVisible)
                    .limit(25);

            // Use the query for pagination
            // ...
        }
    });

Kotlin+KTX

// Construct query for first 25 cities, ordered by population
val first = db.collection("cities")
        .orderBy("population")
        .limit(25)

first.get()
        .addOnSuccessListener { documentSnapshots ->
            // ...

            // Get the last visible document
            val lastVisible = documentSnapshots.documents[documentSnapshots.size() - 1]

            // Construct a new query starting at this document,
            // get the next 25 cities.
            val next = db.collection("cities")
                    .orderBy("population")
                    .startAfter(lastVisible)
                    .limit(25)

            // Use the query for pagination
            // ...
        }

Dart

// Construct query for first 25 cities, ordered by population
final first = db.collection("cities").orderBy("population").limit(25);

first.get().then(
  (documentSnapshots) {
    // Get the last visible document
    final lastVisible = documentSnapshots.docs[documentSnapshots.size - 1];

    // Construct a new query starting at this document,
    // get the next 25 cities.
    final next = db
        .collection("cities")
        .orderBy("population")
        .startAfter([lastVisible]).limit(25);

    // Use the query for pagination
    // ...
  },
  onError: (e) => print("Error completing: $e"),
);
Джава
// Construct query for first 25 cities, ordered by population.
CollectionReference cities = db.collection("cities");
Query firstPage = cities.orderBy("population").limit(25);

// Wait for the results of the API call, waiting for a maximum of 30 seconds for a result.
ApiFuture<QuerySnapshot> future = firstPage.get();
List<QueryDocumentSnapshot> docs = future.get(30, TimeUnit.SECONDS).getDocuments();

// Construct query for the next 25 cities.
QueryDocumentSnapshot lastDoc = docs.get(docs.size() - 1);
Query secondPage = cities.orderBy("population").startAfter(lastDoc).limit(25);

future = secondPage.get();
docs = future.get(30, TimeUnit.SECONDS).getDocuments();
Питон
cities_ref = db.collection(u'cities')
first_query = cities_ref.order_by(u'population').limit(3)

# Get the last document from the results
docs = first_query.stream()
last_doc = list(docs)[-1]

# Construct a new query starting at this document
# Note: this will not have the desired effect if
# multiple cities have the exact same population value
last_pop = last_doc.to_dict()[u'population']

next_query = (
    cities_ref
    .order_by(u'population')
    .start_after({
        u'population': last_pop
    })
    .limit(3)
)
# Use the query for pagination
# ...

Python

cities_ref = db.collection("cities")
first_query = cities_ref.order_by("population").limit(3)

# Get the last document from the results
docs = [d async for d in first_query.stream()]
last_doc = list(docs)[-1]

# Construct a new query starting at this document
# Note: this will not have the desired effect if
# multiple cities have the exact same population value
last_pop = last_doc.to_dict()["population"]

next_query = (
    cities_ref.order_by("population").start_after({"population": last_pop}).limit(3)
)
# Use the query for pagination
# ...
С++
// Construct query for first 25 cities, ordered by population
Query first = db->Collection("cities").OrderBy("population").Limit(25);

first.Get().OnCompletion([db](const Future<QuerySnapshot>& future) {
  if (future.error() != Error::kErrorOk) {
    // Handle error...
    return;
  }

  // Get the last visible document
  const QuerySnapshot& document_snapshots = *future.result();
  std::vector<DocumentSnapshot> documents = document_snapshots.documents();
  const DocumentSnapshot& last_visible = documents.back();

  // Construct a new query starting at this document,
  // get the next 25 cities.
  Query next = db->Collection("cities")
                   .OrderBy("population")
                   .StartAfter(last_visible)
                   .Limit(25);

  // Use the query for pagination
  // ...
});
Node.js
const first = db.collection('cities')
  .orderBy('population')
  .limit(3);

const snapshot = await first.get();

// Get the last document
const last = snapshot.docs[snapshot.docs.length - 1];

// Construct a new query starting at this document.
// Note: this will not have the desired effect if multiple
// cities have the exact same population value.
const next = db.collection('cities')
  .orderBy('population')
  .startAfter(last.data().population)
  .limit(3);

// Use the query for pagination
// ...
Идти
cities := client.Collection("cities")

// Get the first 25 cities, ordered by population.
firstPage := cities.OrderBy("population", firestore.Asc).Limit(25).Documents(ctx)
docs, err := firstPage.GetAll()
if err != nil {
	return err
}

// Get the last document.
lastDoc := docs[len(docs)-1]

// Construct a new query to get the next 25 cities.
secondPage := cities.OrderBy("population", firestore.Asc).
	StartAfter(lastDoc.Data()["population"]).
	Limit(25)

// ...
PHP
$citiesRef = $db->collection('samples/php/cities');
$firstQuery = $citiesRef->orderBy('population')->limit(3);

# Get the last document from the results
$documents = $firstQuery->documents();
$lastPopulation = 0;
foreach ($documents as $document) {
    $lastPopulation = $document['population'];
}

# Construct a new query starting at this document
# Note: this will not have the desired effect if multiple cities have the exact same population value
$nextQuery = $citiesRef->orderBy('population')->startAfter([$lastPopulation]);
$snapshot = $nextQuery->documents();
Единство
CollectionReference citiesRef = db.Collection("cities");
Query firstQuery = citiesRef.OrderBy("Population").Limit(3);

// Get the last document from the results
firstQuery.GetSnapshotAsync().ContinueWith((querySnapshotTask) =>
{
    long lastPopulation = 0;
    foreach (DocumentSnapshot documentSnapshot in querySnapshotTask.Result.Documents)
    {
        lastPopulation = documentSnapshot.GetValue<long>("Population");
    }

    // Construct a new query starting at this document.
    // Note: this will not have the desired effect if multiple cities have the exact same population value
    Query secondQuery = citiesRef.OrderBy("Population").StartAfter(lastPopulation);
    Task<QuerySnapshot> secondQuerySnapshot = secondQuery.GetSnapshotAsync();
С#
CollectionReference citiesRef = db.Collection("cities");
Query firstQuery = citiesRef.OrderBy("Population").Limit(3);

// Get the last document from the results
QuerySnapshot querySnapshot = await firstQuery.GetSnapshotAsync();
long lastPopulation = 0;
foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
{
    lastPopulation = documentSnapshot.GetValue<long>("Population");
}

// Construct a new query starting at this document.
// Note: this will not have the desired effect if multiple cities have the exact same population value
Query secondQuery = citiesRef.OrderBy("Population").StartAfter(lastPopulation);
QuerySnapshot secondQuerySnapshot = await secondQuery.GetSnapshotAsync();
Рубин
cities_ref  = firestore.col collection_path
first_query = cities_ref.order("population").limit(3)

# Get the last document from the results.
last_population = 0
first_query.get do |city|
  last_population = city.data[:population]
end

# Construct a new query starting at this document.
# Note: this will not have the desired effect if multiple cities have the exact same population value.
second_query = cities_ref.order("population").start_after(last_population)
second_query.get do |city|
  puts "Document #{city.document_id} returned by paginated query cursor."
end

Установить курсор на основе нескольких полей

При использовании курсора на основе значения поля (не DocumentSnapshot) положение курсора можно уточнить, добавив дополнительные поля. Это особенно полезно, если ваш набор данных включает в себя несколько документов, все из которых имеют одинаковое значение поля курсора, что делает позицию курсора неоднозначной. Вы можете добавить к курсору дополнительные значения поля, чтобы дополнительно указать начальную или конечную точку и уменьшить неоднозначность.

Например, в наборе данных, содержащем все города с названием «Спрингфилд» в США, будет несколько начальных точек для набора запросов, который будет начинаться со «Спрингфилд»:

Города
Имя Состояние
Спрингфилд Массачусетс
Спрингфилд Миссури
Спрингфилд Висконсин

Чтобы начать с определенного Спрингфилда, вы можете добавить состояние в качестве вторичного условия в предложение курсора.

Web version 9

// Will return all Springfields
import { collection, query, orderBy, startAt } from "firebase/firestore";  
const q1 = query(collection(db, "cities"),
   orderBy("name"),
   orderBy("state"),
   startAt("Springfield"));

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
const q2 = query(collection(db, "cities"),
   orderBy("name"),
   orderBy("state"),
   startAt("Springfield", "Missouri"));

Web version 8

// Will return all Springfields
db.collection("cities")
   .orderBy("name")
   .orderBy("state")
   .startAt("Springfield");

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
db.collection("cities")
   .orderBy("name")
   .orderBy("state")
   .startAt("Springfield", "Missouri");
Быстрый
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Will return all Springfields
db.collection("cities")
    .order(by: "name")
    .order(by: "state")
    .start(at: ["Springfield"])

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
db.collection("cities")
    .order(by: "name")
    .order(by: "state")
    .start(at: ["Springfield", "Missouri"])
Цель-C
Примечание. Этот продукт недоступен для целей watchOS и App Clip.
// Will return all Springfields
[[[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"name"]
    queryOrderedByField:@"state"]
    queryStartingAtValues:@[ @"Springfield" ]];
// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
[[[[db collectionWithPath:@"cities"]
   queryOrderedByField:@"name"]
   queryOrderedByField:@"state"]
   queryStartingAtValues:@[ @"Springfield", @"Missouri" ]];

Java

// Will return all Springfields
db.collection("cities")
        .orderBy("name")
        .orderBy("state")
        .startAt("Springfield");

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
db.collection("cities")
        .orderBy("name")
        .orderBy("state")
        .startAt("Springfield", "Missouri");

Kotlin+KTX

// Will return all Springfields
db.collection("cities")
        .orderBy("name")
        .orderBy("state")
        .startAt("Springfield")

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
db.collection("cities")
        .orderBy("name")
        .orderBy("state")
        .startAt("Springfield", "Missouri")

Dart

// Will return all Springfields
db
    .collection("cities")
    .orderBy("name")
    .orderBy("state")
    .startAt(["Springfield"]);

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
db
    .collection("cities")
    .orderBy("name")
    .orderBy("state")
    .startAt(["Springfield", "Missouri"]);
Джава
// Will return all Springfields
Query query1 = db.collection("cities").orderBy("name").orderBy("state").startAt("Springfield");

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
Query query2 =
    db.collection("cities").orderBy("name").orderBy("state").startAt("Springfield", "Missouri");
питон
start_at_name = (
    db.collection(u'cities')
    .order_by(u'name')
    .start_at({
        u'name': u'Springfield'
    })
)

start_at_name_and_state = (
    db.collection(u'cities')
    .order_by(u'name')
    .order_by(u'state')
    .start_at({
        u'name': u'Springfield',
        u'state': u'Missouri'
    })
)

Python

start_at_name = (
    db.collection("cities")
    .order_by("name")
    .order_by("state")
    .start_at({"name": "Springfield"})
)

start_at_name_and_state = (
    db.collection("cities")
    .order_by("name")
    .order_by("state")
    .start_at({"name": "Springfield", "state": "Missouri"})
)
С++
// This is not yet supported.
Node.js
// Will return all Springfields
const startAtNameRes = await db.collection('cities')
  .orderBy('name')
  .orderBy('state')
  .startAt('Springfield')
  .get();

// Will return 'Springfield, Missouri' and 'Springfield, Wisconsin'
const startAtNameAndStateRes = await db.collection('cities')
  .orderBy('name')
  .orderBy('state')
  .startAt('Springfield', 'Missouri')
  .get();
Идти
// Will return all Springfields.
client.Collection("cities").
	OrderBy("name", firestore.Asc).
	OrderBy("state", firestore.Asc).
	StartAt("Springfield")

// Will return Springfields where state comes after Wisconsin.
client.Collection("cities").
	OrderBy("name", firestore.Asc).
	OrderBy("state", firestore.Asc).
	StartAt("Springfield", "Wisconsin")
PHP
// Will return all Springfields
$query1 = $db
    ->collection('samples/php/cities')
    ->orderBy('name')
    ->orderBy('state')
    ->startAt(['Springfield']);

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
$query2 = $db
    ->collection('samples/php/cities')
    ->orderBy('name')
    ->orderBy('state')
    ->startAt(['Springfield', 'Missouri']);
Единство
Query query1 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield");
Query query2 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield", "Missouri");
С#
Query query1 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield");
Query query2 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield", "Missouri");
Рубин
# Will return all Springfields
query1 = firestore.col(collection_path).order("name").order("state").start_at("Springfield")

# Will return "Springfield, Missouri" and "Springfield, Wisconsin"
query2 = firestore.col(collection_path).order("name").order("state").start_at(["Springfield", "Missouri"])