Commandez et limitez les données avec Cloud Firestore

Cloud Firestore fournit une fonctionnalité de requête puissante pour spécifier les documents que vous souhaitez récupérer à partir d'une collection. Ces requêtes peuvent également être utilisées avec get() ou addSnapshotListener() , comme décrit dans Get Data .

Données de commande et de limite

Par défaut, une requête récupère tous les documents qui satisfont la requête dans l'ordre croissant par ID de document. Vous pouvez spécifier l'ordre de tri de vos données à l'aide de orderBy() , et vous pouvez limiter le nombre de documents récupérés à l'aide de limit() .

Par exemple, vous pouvez interroger les 3 premières villes par ordre alphabétique avec :

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

const q = query(citiesRef, orderBy("name"), limit(3));
order_and_limit.js

citiesRef.orderBy("name").limit(3);
test.firestore.js

citiesRef.order(by: "name").limit(to: 3)
ViewController.swift

[[citiesRef queryOrderedByField:@"name"] queryLimitedTo:3];
ViewController.m

citiesRef.orderBy("name").limit(3)
DocSnippets.kt

citiesRef.orderBy("name").limit(3);
DocSnippets.java

final citiesRef = db.collection("cities");
citiesRef.orderBy("name").limit(3);
firestore.dart

Query query = cities.orderBy("name").limit(3);
Query query = cities.orderBy("name").limitToLast(3);
QueryDataSnippets.java

cities_ref = db.collection("cities")
query = cities_ref.order_by("name").limit_to_last(2)
results = query.get()
snippets.py

cities_ref = db.collection("cities")
query = cities_ref.order_by("name").limit_to_last(2)
results = await query.get()
snippets.py

cities_ref.OrderBy("name").Limit(3);
snippets.cpp

const firstThreeRes = await citiesRef.orderBy('name').limit(3).get();
index.js

query := cities.OrderBy("name", firestore.Asc).Limit(3)
query := cities.OrderBy("name", firestore.Asc).LimitToLast(3)
query.go

$query = $citiesRef->orderBy('name')->limit(3);
query_order_limit.php

Query query = citiesRef.OrderBy("Name").Limit(3);

Query query = citiesRef.OrderBy("Name").Limit(3);
Program.cs

query = cities_ref.order("name").limit(3)
order_limit_data.rb

Vous pouvez également trier par ordre décroissant pour obtenir les 3 dernières villes :

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

const q = query(citiesRef, orderBy("name", "desc"), limit(3));
order_and_limit_desc.js

citiesRef.orderBy("name", "desc").limit(3);
test.firestore.js

citiesRef.order(by: "name", descending: true).limit(to: 3)
ViewController.swift

[[citiesRef queryOrderedByField:@"name" descending:YES] queryLimitedTo:3];
ViewController.m

citiesRef.orderBy("name", Query.Direction.DESCENDING).limit(3)
DocSnippets.kt

citiesRef.orderBy("name", Direction.DESCENDING).limit(3);
DocSnippets.java

final citiesRef = db.collection("cities");
citiesRef.orderBy("name", descending: true).limit(3);
firestore.dart

Query query = cities.orderBy("name", Direction.DESCENDING).limit(3);
QueryDataSnippets.java

cities_ref = db.collection(u'cities')
query = cities_ref.order_by(
    u'name', direction=firestore.Query.DESCENDING).limit(3)
results = query.stream()
snippets.py

cities_ref = db.collection("cities")
query = cities_ref.order_by("name", direction=firestore.Query.DESCENDING).limit(3)
results = query.stream()
snippets.py

cities_ref.OrderBy("name", Query::Direction::kDescending).Limit(3);
snippets.cpp

const lastThreeRes = await citiesRef.orderBy('name', 'desc').limit(3).get();
index.js

query := cities.OrderBy("name", firestore.Desc).Limit(3)
query.go

$query = $citiesRef->orderBy('name', 'DESC')->limit(3);
query_order_desc_limit.php

Query query = citiesRef.OrderByDescending("Name").Limit(3);

Query query = citiesRef.OrderByDescending("Name").Limit(3);
Program.cs

query = cities_ref.order("name", "desc").limit(3)
order_limit_data.rb

Vous pouvez également trier par plusieurs champs. Par exemple, si vous vouliez trier par état, et au sein de chaque état trier par population en ordre décroissant :

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

const q = query(citiesRef, orderBy("state"), orderBy("population", "desc"));
order_multiple.js

citiesRef.orderBy("state").orderBy("population", "desc");
test.firestore.js

citiesRef
    .order(by: "state")
    .order(by: "population", descending: true)
ViewController.swift

[[citiesRef queryOrderedByField:@"state"] queryOrderedByField:@"population" descending:YES];
ViewController.m

citiesRef.orderBy("state").orderBy("population", Query.Direction.DESCENDING)
DocSnippets.kt

citiesRef.orderBy("state").orderBy("population", Direction.DESCENDING);
DocSnippets.java

final citiesRef = db.collection("cities");
citiesRef.orderBy("state").orderBy("population", descending: true);
firestore.dart

Query query = cities.orderBy("state").orderBy("population", Direction.DESCENDING);
QueryDataSnippets.java

cities_ref = db.collection(u'cities')
cities_ref.order_by(u'state').order_by(
    u'population', direction=firestore.Query.DESCENDING)
snippets.py

cities_ref = db.collection("cities")
cities_ref.order_by("state").order_by(
    "population", direction=firestore.Query.DESCENDING
)
snippets.py

cities_ref.OrderBy("state").OrderBy("name", Query::Direction::kDescending);
snippets.cpp

const byStateByPopRes = await citiesRef.orderBy('state').orderBy('population', 'desc').get();
index.js

query := client.Collection("cities").OrderBy("state", firestore.Asc).OrderBy("population", firestore.Desc)
query.go

$query = $citiesRef->orderBy('state')->orderBy('population', 'DESC');
query_order_multi.php

Query query = citiesRef.OrderBy("State").OrderByDescending("Population");

Query query = citiesRef.OrderBy("State").OrderByDescending("Population");
Program.cs

query = cities_ref.order("state").order("population", "desc")
order_limit_data.rb

Vous pouvez combiner les filtres where( where() avec orderBy() et limit() . Dans l'exemple suivant, les requêtes définissent un seuil de population, trient par population dans l'ordre croissant et renvoient uniquement les premiers résultats qui dépassent le seuil :

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

const q = query(citiesRef, where("population", ">", 100000), orderBy("population"), limit(2));
filter_and_order.js

citiesRef.where("population", ">", 100000).orderBy("population").limit(2);
test.firestore.js

citiesRef
    .whereField("population", isGreaterThan: 100000)
    .order(by: "population")
    .limit(to: 2)
ViewController.swift

[[[citiesRef queryWhereField:@"population" isGreaterThan:@100000]
    queryOrderedByField:@"population"]
    queryLimitedTo:2];
ViewController.m

citiesRef.whereGreaterThan("population", 100000).orderBy("population").limit(2)
DocSnippets.kt

citiesRef.whereGreaterThan("population", 100000).orderBy("population").limit(2);
DocSnippets.java

final citiesRef = db.collection("cities");
citiesRef
    .where("population", isGreaterThan: 100000)
    .orderBy("population")
    .limit(2);
firestore.dart

Query query = cities.whereGreaterThan("population", 2500000L).orderBy("population").limit(2);
QueryDataSnippets.java

cities_ref = db.collection(u'cities')
query = cities_ref.where(
    u'population', u'>', 2500000).order_by(u'population').limit(2)
results = query.stream()
snippets.py

cities_ref = db.collection("cities")
query = cities_ref.where("population", ">", 2500000).order_by("population").limit(2)
results = query.stream()
snippets.py

cities_ref.WhereGreaterThan("population", FieldValue::Integer(100000))
    .OrderBy("population")
    .Limit(2);
snippets.cpp

const biggestRes = await citiesRef.where('population', '>', 2500000)
  .orderBy('population').limit(2).get();
index.js

query := cities.Where("population", ">", 2500000).OrderBy("population", firestore.Desc).Limit(2)
query.go

$query = $citiesRef
    ->where('population', '>', 2500000)
    ->orderBy('population')
    ->limit(2);
query_order_limit_field_valid.php

Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population")
    .Limit(2);

Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population")
    .Limit(2);
Program.cs

query = cities_ref.where("population", ">", 2_500_000).order("population").limit(2)
order_limit_data.rb

Cependant, si vous avez un filtre avec une comparaison de plage ( < , <= , > , >= ), votre premier tri doit être sur le même champ, voir la liste des limitations de orderBy() ci-dessous.

Limites

Notez les restrictions suivantes pour les clauses orderBy() :

• Une clause orderBy() filtre également l'existence des champs donnés. Le jeu de résultats n'inclura pas les documents qui ne contiennent pas les champs donnés.

• Si vous incluez un filtre avec une comparaison de plage ( < , <= , > , >= ), votre premier tri doit être sur le même champ :

  Valide : Filtre de plage et orderBy sur le même champ

  Web version 9

  import { query, where, orderBy } from "firebase/firestore";  
  
  const q = query(citiesRef, where("population", ">", 100000), orderBy("population"));
  valid_filter_and_order.js

  Web version 8

  citiesRef.where("population", ">", 100000).orderBy("population");
  test.firestore.js

  Rapide

  Remarque : ce produit n'est pas disponible sur les cibles watchOS et App Clip.

  citiesRef
      .whereField("population", isGreaterThan: 100000)
      .order(by: "population")
  ViewController.swift

  Objectif c

  Remarque : ce produit n'est pas disponible sur les cibles watchOS et App Clip.

  [[citiesRef queryWhereField:@"population" isGreaterThan:@100000]
      queryOrderedByField:@"population"];
  ViewController.m

  Kotlin+KTX

  citiesRef.whereGreaterThan("population", 100000).orderBy("population")
  DocSnippets.kt

  Java

  citiesRef.whereGreaterThan("population", 100000).orderBy("population");
  DocSnippets.java

  Dart

  final citiesRef = db.collection("cities");
  citiesRef.where("population", isGreaterThan: 100000).orderBy("population");
  firestore.dart

  Java

  Query query = cities.whereGreaterThan("population", 2500000L).orderBy("population");
  QueryDataSnippets.java

  Python

  cities_ref = db.collection(u'cities')
  query = cities_ref.where(
      u'population', u'>', 2500000).order_by(u'population')
  results = query.stream()
  snippets.py

  Python

  cities_ref = db.collection("cities")
  query = cities_ref.where("population", ">", 2500000).order_by("population")
  results = query.stream()
  snippets.py

  Node.js

  citiesRef.where('population', '>', 2500000).orderBy('population');
  index.js

  Va

  query := cities.Where("population", ">", 2500000).OrderBy("population", firestore.Asc)
  query.go

  PHP

  PHP

  Pour en savoir plus sur l'installation et la création d'un client Cloud Firestore, reportez-vous à Bibliothèques clientes Cloud Firestore .

  $query = $citiesRef
      ->where('population', '>', 2500000)
      ->orderBy('population');
  query_order_with_filter.php

  Unité

  Query query = citiesRef
      .WhereGreaterThan("Population", 2500000)
      .OrderBy("Population");

  C#

  Query query = citiesRef
      .WhereGreaterThan("Population", 2500000)
      .OrderBy("Population");
  Program.cs

  Rubis

  query = cities_ref.where("population", ">", 2_500_000).order("population")
  order_limit_data.rb

  Non valide : filtre de plage et premier orderBy sur différents champs

  Web version 9

  import { query, where, orderBy } from "firebase/firestore";  
  
  const q = query(citiesRef, where("population", ">", 100000), orderBy("country"));
  invalid_filter_and_order.js

  Web version 8

  citiesRef.where("population", ">", 100000).orderBy("country");
  test.firestore.js

  Rapide

  Remarque : ce produit n'est pas disponible sur les cibles watchOS et App Clip.

  citiesRef
      .whereField("population", isGreaterThan: 100000)
      .order(by: "country")
  ViewController.swift

  Objectif c

  Remarque : ce produit n'est pas disponible sur les cibles watchOS et App Clip.

  [[citiesRef queryWhereField:@"population" isGreaterThan:@100000] queryOrderedByField:@"country"];
  ViewController.m

  Kotlin+KTX

  citiesRef.whereGreaterThan("population", 100000).orderBy("country")
  DocSnippets.kt

  Java

  citiesRef.whereGreaterThan("population", 100000).orderBy("country");
  DocSnippets.java

  Dart

  final citiesRef = db.collection("cities");
  citiesRef.where("population", isGreaterThan: 100000).orderBy("country");
  firestore.dart

  Java

  Query query = cities.whereGreaterThan("population", 2500000L).orderBy("country");
  QueryDataSnippets.java

  Python

  cities_ref = db.collection(u'cities')
  query = cities_ref.where(u'population', u'>', 2500000).order_by(u'country')
  results = query.stream()
  snippets.py

  Python

  cities_ref = db.collection("cities")
  query = cities_ref.where("population", ">", 2500000).order_by("country")
  results = query.stream()
  snippets.py

  C++

  // BAD EXAMPLE -- will crash the program:
  cities_ref.WhereGreaterThan("population", FieldValue::Integer(100000))
      .OrderBy("country");
  snippets.cpp

  Node.js

  citiesRef.where('population', '>', 2500000).orderBy('country');
  index.js

  Va

  // Note: This is an invalid query. It violates the constraint that range
  // and order by are required to be on the same field.
  query := cities.Where("population", ">", 2500000).OrderBy("country", firestore.Asc)
  query.go

  PHP

  PHP

  Pour en savoir plus sur l'installation et la création d'un client Cloud Firestore, reportez-vous à Bibliothèques clientes Cloud Firestore .

  $invalidRangeQuery = $citiesRef
      ->where('population', '>', 2500000)
      ->orderBy('country');
  query_order_field_invalid.php

  Unité

  Query query = citiesRef
      .WhereGreaterThan("Population", 2500000)
      .OrderBy("Country");

  C#

  Query query = citiesRef
      .WhereGreaterThan("Population", 2500000)
      .OrderBy("Country");
  Program.cs

  Rubis

  query = cities_ref.where("population", ">", 2_500_000).order("country")
  order_limit_data.rb

• Vous ne pouvez pas ordonner votre requête par n'importe quel champ inclus dans une égalité ( = ) ou in une clause.