Dzielenie danych na strony za pomocą kursorów zapytania

Za pomocą kursorów zapytań w Cloud Firestore możesz dzielić dane zwracane przez zapytanie na partie zgodnie z parametrami zdefiniowanymi w zapytaniu.

Kursory zapytań określają punkty początkowe i końcowe zapytania, co umożliwia:

  • Zwróć podzbiór danych.
  • stronicować wyniki zapytania,

Aby jednak zdefiniować konkretny zakres zapytania, użyj metody opisanej w artykule Proste zapytania.where()

Dodawanie prostego kursora do zapytania

Aby zdefiniować punkt początkowy zapytania, użyj metody startAt() lub startAfter(). Metoda startAt() obejmuje punkt początkowy, a metoda startAfter() go wyklucza.

Jeśli na przykład w zapytaniu użyjesz znaku startAt(A), zwróci on cały alfabet. Jeśli zamiast tego użyjesz startAfter(A), zwróci ona wartość B-Z.

Web

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

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

Web

citiesRef.orderBy("population").startAt(1000000);
test.firestore.js
Swift
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// Get all cities with population over one million, ordered by population.
db.collection("cities")
  .order(by: "population")
  .start(at: [1000000])
ViewController.swift
Objective-C
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// Get all cities with population over one million, ordered by population.
[[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"population"]
    queryStartingAtValues:@[ @1000000 ]];
ViewController.m

Kotlin

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

Java

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

Dart

db.collection("cities").orderBy("population").startAt([1000000]);
firestore.dart
Java
Query query = cities.orderBy("population").startAt(4921000L);
QueryDataSnippets.java
Python
cities_ref = db.collection("cities")
query_start_at = cities_ref.order_by("population").start_at({"population": 1000000})
snippets.py

Python

cities_ref = db.collection("cities")
query_start_at = cities_ref.order_by("population").start_at({"population": 1000000})
snippets.py
C++
// Get all cities with a population >= 1,000,000, ordered by population,
db->Collection("cities")
    .OrderBy("population")
    .StartAt({FieldValue::Integer(1000000)});
snippets.cpp
Node.js
const startAtRes = await db.collection('cities')
  .orderBy('population')
  .startAt(1000000)
  .get();
index.js
Go
query := client.Collection("cities").OrderBy("population", firestore.Asc).StartAt(1000000)
query.go
PHP

PHP

Więcej informacji o instalowaniu i tworzeniu klienta Cloud Firestore znajdziesz w sekcji Cloud FirestoreBiblioteki klienta. 

$query = $citiesRef
    ->orderBy('population')
    ->startAt([1000000]);
query_cursor_start_at_field_value_single.php
Unity
Query query = citiesRef.OrderBy("Population").StartAt(1000000);
C#
Query query = citiesRef.OrderBy("Population").StartAt(1000000);
Program.cs
Ruby
query = cities_ref.order("population").start_at(1_000_000)
paginate_data.rb

Podobnie użyj metod endAt() lub endBefore(), aby zdefiniować punkt końcowy wyników zapytania.

Web

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

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

Web

citiesRef.orderBy("population").endAt(1000000);
test.firestore.js
Swift
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// Get all cities with population less than one million, ordered by population.
db.collection("cities")
  .order(by: "population")
  .end(at: [1000000])
ViewController.swift
Objective-C
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// Get all cities with population less than one million, ordered by population.
[[[db collectionWithPath:@"cities"]
    queryOrderedByField:@"population"]
    queryEndingAtValues:@[ @1000000 ]];
ViewController.m

Kotlin

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

Java

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

Dart

db.collection("cities").orderBy("population").endAt([1000000]);
firestore.dart
Java
Query query = cities.orderBy("population").endAt(4921000L);
QueryDataSnippets.java
Python
cities_ref = db.collection("cities")
query_end_at = cities_ref.order_by("population").end_at({"population": 1000000})
snippets.py

Python

cities_ref = db.collection("cities")
query_end_at = cities_ref.order_by("population").end_at({"population": 1000000})
snippets.py
C++
// Get all cities with a population <= 1,000,000, ordered by population,
db->Collection("cities")
    .OrderBy("population")
    .EndAt({FieldValue::Integer(1000000)});
snippets.cpp
Node.js
const endAtRes = await db.collection('cities')
  .orderBy('population')
  .endAt(1000000)
  .get();
index.js
Go
query := client.Collection("cities").OrderBy("population", firestore.Asc).EndAt(1000000)
query.go
PHP

PHP

Więcej informacji o instalowaniu i tworzeniu klienta Cloud Firestore znajdziesz w sekcji Cloud FirestoreBiblioteki klienta. 

$query = $citiesRef
    ->orderBy('population')
    ->endAt([1000000]);
query_cursor_end_at_field_value_single.php
Unity
Query query = citiesRef.OrderBy("Population").EndAt(1000000);
C#
Query query = citiesRef.OrderBy("Population").EndAt(1000000);
Program.cs
Ruby
query = cities_ref.order("population").end_at(1_000_000)
paginate_data.rb

Używanie zrzutu dokumentu do definiowania kursora zapytania

Możesz też przekazać do klauzuli kursora migawkę dokumentu jako punkt początkowy lub końcowy kursora zapytania. Wartości w migawce dokumentu służą jako wartości w kursorze zapytania.

Możesz na przykład zrobić zrzut dokumentu „San Francisco” w zbiorze danych miast i ich populacji. Następnie użyj zrzutu dokumentu jako punktu początkowego kursora zapytania o populację. Zapytanie zwróci wszystkie miasta, których populacja jest większa lub równa populacji San Francisco, zgodnie z definicją w migawce dokumentu.

Web

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));
// ...
start_doc.js

Web

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);

    // ...
});
test.firestore.js
Swift
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
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)
  }
ViewController.swift
Objective-C
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
[[[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];
    }];
ViewController.m

Kotlin

// 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)

        // ...
    }
DocSnippets.kt

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);

                // ...
            }
        });
DocSnippets.java

Dart

db.collection("cities").doc("SF").get().then(
  (documentSnapshot) {
    final biggerThanSf = db
        .collection("cities")
        .orderBy("population")
        .startAtDocument(documentSnapshot);
  },
  onError: (e) => print("Error: $e"),
);
firestore.dart
Java
// 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);
QueryDataSnippets.java
Python
doc_ref = db.collection("cities").document("SF")

snapshot = doc_ref.get()
start_at_snapshot = (
    db.collection("cities").order_by("population").start_at(snapshot)
)
snippets.py

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)
)
snippets.py
C++
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});
        // ...
      }
    });
snippets.cpp
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();
index.js
Go
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)
query.go
PHP

PHP

Więcej informacji o instalowaniu i tworzeniu klienta Cloud Firestore znajdziesz w sekcji Cloud FirestoreBiblioteki klienta. 

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

$query = $citiesRef
    ->orderBy('population')
    ->startAt($snapshot);
query_cursor_start_at_document.php
Unity
CollectionReference citiesRef = db.Collection("cities");
DocumentReference docRef = citiesRef.Document("SF");
docRef.GetSnapshotAsync().ContinueWith((snapshotTask) =>
{
    Query query = citiesRef.OrderBy("Population").StartAt(snapshotTask.Result);
});
C#
CollectionReference citiesRef = db.Collection("cities");
DocumentReference docRef = citiesRef.Document("SF");
DocumentSnapshot snapshot = await docRef.GetSnapshotAsync();
Query query = citiesRef.OrderBy("Population").StartAt(snapshot);
Program.cs
Ruby
doc_ref = firestore.doc "#{collection_path}/SF"
snapshot = doc_ref.get
query = cities_ref.order("population").start_at(snapshot)
paginate_data.rb

Stronicowanie zapytania

Stronicuj zapytania, łącząc kursory zapytań z metodą limit(). Na przykład użyj ostatniego dokumentu w partii jako początku kursora dla następnej partii.

Web

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));
paginate.js

Web

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);
});
test.firestore.js
Swift
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// 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.
  // ...
}
ViewController.swift
Objective-C
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
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.
  // ...
}];
ViewController.m

Kotlin

// 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
        // ...
    }
DocSnippets.kt

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
            // ...
        }
    });
DocSnippets.java

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")
        .startAfterDocument(lastVisible)
        .limit(25);

    // Use the query for pagination
    // ...
  },
  onError: (e) => print("Error completing: $e"),
);
firestore.dart
Java
// 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();
QueryDataSnippets.java
Python
cities_ref = db.collection("cities")
first_query = cities_ref.order_by("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()["population"]

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

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
# ...
snippets.py
C++
// 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
  // ...
});
snippets.cpp
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
// ...
index.js
Go
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)

// ...
query.go
PHP

PHP

Więcej informacji o instalowaniu i tworzeniu klienta Cloud Firestore znajdziesz w sekcji Cloud FirestoreBiblioteki klienta. 

$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();
query_cursor_pagination.php
Unity
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();
C#
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();
Program.cs
Ruby
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
paginate_data.rb

Ustawianie kursora na podstawie wielu pól

Jeśli używasz kursora opartego na wartości pola (nie na obiekcie DocumentSnapshot), możesz zwiększyć precyzję jego pozycji, dodając dodatkowe pola. Jest to szczególnie przydatne, jeśli zbiór danych zawiera wiele dokumentów, które mają tę samą wartość w polu kursora, co sprawia, że jego pozycja jest niejednoznaczna. Możesz dodać do kursora dodatkowe wartości pól, aby dokładniej określić punkt początkowy lub końcowy i zmniejszyć niejednoznaczność.

Na przykład w zbiorze danych zawierającym wszystkie miasta o nazwie „Springfield” w Stanach Zjednoczonych będzie wiele punktów początkowych dla zapytania ustawionego na rozpoczęcie od „Springfield”:

Miasta
Nazwa Stan
Springfield Massachusetts
Springfield Missouri
Springfield Wisconsin

Aby zacząć od konkretnego miasta Springfield, możesz dodać stan jako warunek dodatkowy w klauzuli kursora.

Web

// 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"));
start_multiple_orderby.js

Web

// 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");
test.firestore.js
Swift
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// 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"])
ViewController.swift
Objective-C
Uwaga: ten produkt nie jest dostępny na platformach watchOS i w przypadku klipów aplikacji. 
// 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" ]];
ViewController.m

Kotlin

// 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")
DocSnippets.kt

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");
DocSnippets.java

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"]);
firestore.dart
Java
// 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");
QueryDataSnippets.java
Python
start_at_name = (
    db.collection("cities").order_by("name").start_at({"name": "Springfield"})
)

start_at_name_and_state = (
    db.collection("cities")
    .order_by("name")
    .order_by("state")
    .start_at({"name": "Springfield", "state": "Missouri"})
)
snippets.py

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"})
)
snippets.py
C++
// 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();
index.js
Go
// 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")
query.go
PHP

PHP

Więcej informacji o instalowaniu i tworzeniu klienta Cloud Firestore znajdziesz w sekcji Cloud FirestoreBiblioteki klienta. 

// 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']);
query_cursor_start_at_field_value_multi.php
Unity
Query query1 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield");
Query query2 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield", "Missouri");
C#
Query query1 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield");
Query query2 = db.Collection("cities").OrderBy("Name").OrderBy("State").StartAt("Springfield", "Missouri");
Program.cs
Ruby
# 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"])
paginate_data.rb