O Google tem o compromisso de promover a igualdade racial para as comunidades negras. Saiba como.

Executar consultas simples e compostas no Cloud Firestore

O Cloud Firestore tem uma funcionalidade de consulta eficiente que permite a você especificar os documentos que pretende recuperar de uma coleção ou grupo de coleções. Essas consultas também podem ser usadas com get() ou addSnapshotListener(), conforme descrito em Receber dados e Receber atualizações em tempo real.

Dados de exemplo

Para começar, escreva alguns dados sobre cidades para demonstrarmos diversas formas de leitura:

Site
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
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
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
Java
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
Kotlin
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
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 documents successfully added
ApiFutures.allAsList(futures).get();
QueryDataSnippets.java
Python
class City(object):
    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(
            u'City(name={}, country={}, population={}, capital={}, regions={})'
            .format(self.name, self.country, self.population, self.capital,
                    self.regions))

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

let setSf = citiesRef.doc('SF').set({
  name: 'San Francisco', state: 'CA', country: 'USA',
  capital: false, population: 860000,
  regions: ['west_coast', 'norcal']
});
let setLa = citiesRef.doc('LA').set({
  name: 'Los Angeles', state: 'CA', country: 'USA',
  capital: false, population: 3900000,
  regions: ['west_coast', 'socal']
});
let setDc = citiesRef.doc('DC').set({
  name: 'Washington, D.C.', state: null, country: 'USA',
  capital: true, population: 680000,
  regions: ['east_coast']
});
let setTok = citiesRef.doc('TOK').set({
  name: 'Tokyo', state: null, country: 'Japan',
  capital: true, population: 9000000,
  regions: ['kanto', 'honshu']
});
let setBj = citiesRef.doc('BJ').set({
  name: 'Beijing', state: null, country: 'China',
  capital: true, population: 21500000,
  regions: ['jingjinji', 'hebei']
});
index.js
Go
cities := []struct {
	id string
	c  City
}{
	{
		id: "SF",
		c: City{Name: "San Francisco", State: "CA", Country: "USA",
			Capital: false, Population: 860000,
			Regions: []string{"west_coast", "norcal"}},
	},
	{
		id: "LA",
		c: City{Name: "Los Angeles", State: "CA", Country: "USA",
			Capital: false, Population: 3900000,
			Regions: []string{"west_coast", "socal"}},
	},
	{
		id: "DC",
		c: City{Name: "Washington D.C.", Country: "USA",
			Capital: false, Population: 680000,
			Regions: []string{"east_coast"}},
	},
	{
		id: "TOK",
		c: City{Name: "Tokyo", Country: "Japan",
			Capital: true, Population: 9000000,
			Regions: []string{"kanto", "honshu"}},
	},
	{
		id: "BJ",
		c: City{Name: "Beijing", Country: "China",
			Capital: true, Population: 21500000,
			Regions: []string{"jingjinji", "hebei"}},
	},
}
for _, c := range cities {
	if _, err := client.Collection("cities").Doc(c.id).Set(ctx, c.c); err != nil {
		return err
	}
}
query.go
PHP
$citiesRef = $db->collection('cities');
$citiesRef->document('SF')->set([
    'name' => 'San Francisco',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 860000,
    'regions' => ['west_coast', 'norcal']
]);
$citiesRef->document('LA')->set([
    'name' => 'Los Angeles',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 3900000,
    'regions' => ['west_coast', 'socal']
]);
$citiesRef->document('DC')->set([
    'name' => 'Washington D.C.',
    'state' => null,
    'country' => 'USA',
    'capital' => true,
    'population' => 680000,
    'regions' => ['east_coast']
]);
$citiesRef->document('TOK')->set([
    'name' => 'Tokyo',
    'state' => null,
    'country' => 'Japan',
    'capital' => true,
    'population' => 9000000,
    'regions' => ['kanto', 'honshu']
]);
$citiesRef->document('BJ')->set([
    'name' => 'Beijing',
    'state' => null,
    'country' => 'China',
    'capital' => true,
    'population' => 21500000,
    'regions' => ['jingjinji', 'hebei']
]);
printf('Added example cities data to the cities collection.' . PHP_EOL);
query_create_examples.php
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 },
    { "Regions", new ArrayList{"west_coast", "norcal"} }
});
await citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
    { "Name", "Los Angeles" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 3900000 },
    { "Regions", new ArrayList{"west_coast", "socal"} }
});
await citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
    { "Name", "Washington D.C." },
    { "State", null },
    { "Country", "USA" },
    { "Capital", true },
    { "Population", 680000 },
    { "Regions", new ArrayList{"east_coast"} }
});
await citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
    { "Name", "Tokyo" },
    { "State", null },
    { "Country", "Japan" },
    { "Capital", true },
    { "Population", 9000000 },
    { "Regions", new ArrayList{"kanto", "honshu"} }
});
await citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
    { "Name", "Beijing" },
    { "State", null },
    { "Country", "China" },
    { "Capital", true },
    { "Population", 21500000 },
    { "Regions", new ArrayList{"jingjinji", "hebei"} }
});
Console.WriteLine("Added example cities data to the cities collection.");
Program.cs
Ruby
cities_ref = firestore.col "cities"
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
)
query_data.rb

Consultas simples

A seguinte consulta mostra todas as cidades do estado CA:

Site
// Create a reference to the cities collection
var citiesRef = db.collection("cities");

// Create a query against the collection.
var query = citiesRef.where("state", "==", "CA");
test.firestore.js
Swift
// Create a reference to the cities collection
let citiesRef = db.collection("cities")

// Create a query against the collection.
let query = citiesRef.whereField("state", isEqualTo: "CA")
ViewController.swift
Objective-C
// Create a reference to the cities collection
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];
// Create a query against the collection.
FIRQuery *query = [citiesRef queryWhereField:@"state" isEqualTo:@"CA"];
ViewController.m
Java
// Create a reference to the cities collection
CollectionReference citiesRef = db.collection("cities");

// Create a query against the collection.
Query query = citiesRef.whereEqualTo("state", "CA");
DocSnippets.java
Kotlin
// Create a reference to the cities collection
val citiesRef = db.collection("cities")

// Create a query against the collection.
val query = citiesRef.whereEqualTo("state", "CA")
DocSnippets.kt
Java
// Create a reference to the cities collection
CollectionReference cities = db.collection("cities");
// Create a query against the collection.
Query query = cities.whereEqualTo("state", "CA");
// retrieve  query results asynchronously using query.get()
ApiFuture<QuerySnapshot> querySnapshot = query.get();

for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
QueryDataSnippets.java
Python
# Create a reference to the cities collection
cities_ref = db.collection(u'cities')

# Create a query against the collection
query_ref = cities_ref.where(u'state', u'==', u'CA')
snippets.py
Node.js
// Create a reference to the cities collection
let citiesRef = db.collection('cities');

// Create a query against the collection
let queryRef = citiesRef.where('state', '==', 'CA');
index.js
Go
query := client.Collection("cities").Where("state", "==", "CA")
query.go
PHP
$citiesRef = $db->collection('cities');
$query = $citiesRef->where('state', '=', 'CA');
$snapshot = $query->documents();
foreach ($snapshot as $document) {
    printf('Document %s returned by query state=CA' . PHP_EOL, $document->id());
}
create_query_state.php
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("State", "CA");
QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
{
    Console.WriteLine("Document {0} returned by query State=CA", documentSnapshot.Id);
}
Program.cs
Ruby
cities_ref = firestore.col "cities"

query = cities_ref.where "state", "=", "CA"

query.get do |city|
  puts "Document #{city.document_id} returned by query state=CA."
end
query_data.rb

A consulta a seguir retorna todas as capitais:

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

var query = citiesRef.where("capital", "==", true);
test.firestore.js
Swift
let capitalCities = db.collection("cities").whereField("capital", isEqualTo: true)
ViewController.swift
Objective-C
FIRQuery *capitalCities =
    [[self.db collectionWithPath:@"cities"] queryWhereField:@"capital" isEqualTo:@YES];
ViewController.m
Java
Query capitalCities = db.collection("cities").whereEqualTo("capital", true);
DocSnippets.java
Kotlin
val capitalCities = db.collection("cities").whereEqualTo("capital", true)
DocSnippets.kt
Java
// Create a reference to the cities collection
CollectionReference cities = db.collection("cities");
// Create a query against the collection.
Query query = cities.whereEqualTo("capital", true);
// retrieve  query results asynchronously using query.get()
ApiFuture<QuerySnapshot> querySnapshot = query.get();

for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')

query = cities_ref.where(u'capital', u'==', True)
snippets.py
Node.js
// Create a reference to the cities collection
let citiesRef = db.collection('cities');

// Create a query against the collection
let queryRef = citiesRef.where('capital', '==', true);
index.js
Go
query := client.Collection("cities").Where("capital", "==", true)
query.go
PHP
$citiesRef = $db->collection('cities');
$query = $citiesRef->where('capital', '=', true);
$snapshot = $query->documents();
foreach ($snapshot as $document) {
    printf('Document %s returned by query capital=true' . PHP_EOL, $document->id());
}
create_query_capital.php
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("Capital", true);
QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
{
    Console.WriteLine("Document {0} returned by query Capital=true", documentSnapshot.Id);
}
Program.cs
Ruby
cities_ref = firestore.col "cities"

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

query.get do |city|
  puts "Document #{city.document_id} returned by query capital=true."
end
query_data.rb

Executar uma consulta

Depois de criar um objeto de consulta, use a função get() para recuperar os resultados:

Site
db.collection("cities").where("capital", "==", true)
    .get()
    .then(function(querySnapshot) {
        querySnapshot.forEach(function(doc) {
            // doc.data() is never undefined for query doc snapshots
            console.log(doc.id, " => ", doc.data());
        });
    })
    .catch(function(error) {
        console.log("Error getting documents: ", error);
    });
test.firestore.js
Swift
db.collection("cities").whereField("capital", isEqualTo: true)
    .getDocuments() { (querySnapshot, err) in
        if let err = err {
            print("Error getting documents: \(err)")
        } else {
            for document in querySnapshot!.documents {
                print("\(document.documentID) => \(document.data())")
            }
        }
}
ViewController.swift
Objective-C
[[[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
Java
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
Kotlin
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
//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
docs = db.collection(u'cities').where(u'capital', u'==', True).stream()

for doc in docs:
    print(u'{} => {}'.format(doc.id, doc.to_dict()))
snippets.py
Node.js
let citiesRef = db.collection('cities');
let query = citiesRef.where('capital', '==', true).get()
  .then(snapshot => {
    if (snapshot.empty) {
      console.log('No matching documents.');
      return;
    }

    snapshot.forEach(doc => {
      console.log(doc.id, '=>', doc.data());
    });
  })
  .catch(err => {
    console.log('Error getting documents', err);
  });
index.js
Go
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())
}
retrieve.go
PHP
$citiesRef = $db->collection('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, $snapshot->id());
    }
}
get_multiple_docs.php
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 "cities"

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

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

Consulte Receber dados para conseguir mais informações sobre como recuperar os resultados da consulta. Também é possível adicionar um listener a uma consulta para receber os resultados atuais e detectar futuras atualizações.

Operadores de consulta

O método where() usa três parâmetros: um campo para filtrar, uma operação de comparação e um valor. A comparação pode ser <, <=, ==, >, >= ou array-contains. Para iOS, Android e Java, o operador de comparação é nomeado explicitamente no método.

Alguns exemplos de filtros:

Site
citiesRef.where("state", "==", "CA")
citiesRef.where("population", "<", 100000)
citiesRef.where("name", ">=", "San Francisco")
test.firestore.js
Swift
citiesRef.whereField("state", isEqualTo: "CA")
citiesRef.whereField("population", isLessThan: 100000)
citiesRef.whereField("name", isGreaterThanOrEqualTo: "San Francisco")
ViewController.swift
Objective-C
[citiesRef queryWhereField:@"state" isEqualTo:@"CA"];
[citiesRef queryWhereField:@"population" isLessThan:@100000];
[citiesRef queryWhereField:@"name" isGreaterThanOrEqualTo:@"San Francisco"];
ViewController.m
Java
citiesRef.whereEqualTo("state", "CA");
citiesRef.whereLessThan("population", 100000);
citiesRef.whereGreaterThanOrEqualTo("name", "San Francisco");
DocSnippets.java
Kotlin
citiesRef.whereEqualTo("state", "CA")
citiesRef.whereLessThan("population", 100000)
citiesRef.whereGreaterThanOrEqualTo("name", "San Francisco")
DocSnippets.kt
Java
Query stateQuery = cities.whereEqualTo("state", "CA");
Query populationQuery = cities.whereLessThan("population", 1000000L);
Query nameQuery = cities.whereGreaterThanOrEqualTo("name", "San Francisco");
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')

cities_ref.where(u'state', u'==', u'CA')
cities_ref.where(u'population', u'<', 1000000)
cities_ref.where(u'name', u'>=', u'San Francisco')
snippets.py
Node.js
let stateQuery = citiesRef.where('state', '==', 'CA');
let populationQuery = citiesRef.where('population', '<', 1000000);
let nameQuery = citiesRef.where('name', '>=', 'San Francisco');
index.js
Go
countryQuery := cities.Where("state", "==", "CA")
popQuery := cities.Where("population", "<", 1000000)
cityQuery := cities.Where("name", ">=", "San Francisco")
query.go
PHP
$stateQuery = $citiesRef->where('state', '=', 'CA');
$populationQuery = $citiesRef->where('population', '>', 1000000);
$nameQuery = $citiesRef->where('name', '>=', 'San Francisco');
simple_queries.php
C#
Query stateQuery = citiesRef.WhereEqualTo("State", "CA");
Query populationQuery = citiesRef.WhereGreaterThan("Population", 1000000);
Query nameQuery = citiesRef.WhereGreaterThanOrEqualTo("Name", "San Francisco");
Program.cs
Ruby
state_query      = cities_ref.where "state", "=", "CA"
population_query = cities_ref.where "population", ">", 1_000_000
name_query       = cities_ref.where "name", ">=", "San Francisco"
query_data.rb

Associação de matriz

Use o operador array-contains para filtrar com base nos valores da matriz. Exemplo:

Site
citiesRef.where("regions", "array-contains", "west_coast")
test.firestore.js
Swift
citiesRef
  .whereField("regions", arrayContains: "west_coast")
ViewController.swift
Objective-C
[citiesRef queryWhereField:@"state" arrayContains:@"west_coast"];
ViewController.m
Java
CollectionReference citiesRef = db.collection("cities");

citiesRef.whereArrayContains("regions", "west_coast");
DocSnippets.java
Kotlin
val citiesRef = db.collection("cities")

citiesRef.whereArrayContains("regions", "west_coast")
DocSnippets.kt
Java
CollectionReference citiesRef = db.collection("cities");
Query westCoastQuery = citiesRef.whereArrayContains("regions", "west_coast");
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')

query = cities_ref.where(u'regions', u'array_contains', u'west_coast')
snippets.py
Node.js
let westCoastCities = citiesRef.where('regions', 'array-contains',
  'west_coast');
index.js
Go
query := cities.Where("regions", "array-contains", "west_coast").Documents(ctx)
query.go
PHP
$containsQuery = $citiesRef->where('regions', 'array-contains', 'west_coast');
array_membership.php
C#
Query query = citiesRef.WhereArrayContains("Regions", "west_coast");
Program.cs
Ruby
// Not supported yet

Essa consulta retorna todos os documentos city em que o campo regions é uma matriz contendo west_coast. Se você consultar um valor que tiver várias instâncias na matriz, o documento será incluído nos resultados apenas uma vez.

Consultas compostas

É possível encadear vários métodos where() para criar consultas mais específicas (lógica AND). No entanto, para combinar o operador de igualdade (==) com uma cláusula range ou array-contains (<, <=, >, >= ou array-contains), não se esqueça de criar um índice composto.

Site
citiesRef.where("state", "==", "CO").where("name", "==", "Denver")
citiesRef.where("state", "==", "CA").where("population", "<", 1000000)
test.firestore.js
Swift
citiesRef
    .whereField("state", isEqualTo: "CO")
    .whereField("name", isEqualTo: "Denver")
citiesRef
    .whereField("state", isEqualTo: "CA")
    .whereField("population", isLessThan: 1000000)
ViewController.swift
Objective-C
[[citiesRef queryWhereField:@"state" isEqualTo:@"CO"]
    queryWhereField:@"name" isGreaterThanOrEqualTo:@"Denver"];
[[citiesRef queryWhereField:@"state" isEqualTo:@"CA"]
    queryWhereField:@"population" isLessThan:@1000000];
ViewController.m
Java
citiesRef.whereEqualTo("state", "CO").whereEqualTo("name", "Denver");
citiesRef.whereEqualTo("state", "CA").whereLessThan("population", 1000000);
DocSnippets.java
Kotlin
citiesRef.whereEqualTo("state", "CO").whereEqualTo("name", "Denver")
citiesRef.whereEqualTo("state", "CA").whereLessThan("population", 1000000)
DocSnippets.kt
Java
Query chainedQuery1 = cities.whereEqualTo("state", "CO")
    .whereEqualTo("name", "Denver");
Query chainedQuery2 = cities.whereEqualTo("state", "CA")
    .whereLessThan("population", 1000000L);
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')

sydney_query = cities_ref.where(
    u'state', u'==', u'CO').where(u'name', u'==', u'Denver')
large_us_cities_query = cities_ref.where(
    u'state', u'==', u'CA').where(u'population', u'>', 1000000)
snippets.py
Node.js
citiesRef.where('state', '==', 'CO').where('name', '==', 'Denver');
citiesRef.where('state', '==', 'CA').where('population', '<', 1000000);
index.js
Go
denverQuery := cities.Where("name", "==", "Denver").Where("state", "==", "CO")
caliQuery := cities.Where("state", "==", "CA").Where("population", "<=", 1000000)
query := cities.Where("country", "==", "USA").Where("population", ">", 5000000)
query.go
PHP
$chainedQuery = $citiesRef
    ->where('state', '=', 'CA')
    ->where('name', '=', 'San Francisco');
chained_query.php

$chainedQuery = $citiesRef
    ->where('state', '=', 'CA')
    ->where('population', '<', 1000000);
composite_index_chained_query.php
C#
Query chainedQuery = citiesRef
    .WhereEqualTo("State", "CA")
    .WhereEqualTo("Name", "San Francisco");
Program.cs

Query chainedQuery = citiesRef
    .WhereEqualTo("State", "CA")
    .WhereLessThan("Population", 1000000);
Program.cs
Ruby
chained_query = cities_ref.where("state", "=", "CA").where("name", "=", "San Francisco")
query_data.rb

chained_query = cities_ref.where("state", "=", "CA").where("population", "<", 1_000_000)
query_data.rb

Só podem ser feitas comparações de intervalo (<, <=, >, >=) em um campo único e incluir no máximo uma cláusula array-contains em uma consulta composta:

Válido: filtros de intervalo em apenas um campo

Site
citiesRef.where("state", ">=", "CA").where("state", "<=", "IN")
citiesRef.where("state", "==", "CA").where("population", ">", 1000000)
test.firestore.js
Swift
citiesRef
    .whereField("state", isGreaterThanOrEqualTo: "CA")
    .whereField("state", isLessThanOrEqualTo: "IN")
citiesRef
    .whereField("state", isEqualTo: "CA")
    .whereField("population", isGreaterThan: 1000000)
ViewController.swift
Objective-C
[[citiesRef queryWhereField:@"state" isGreaterThanOrEqualTo:@"CA"]
    queryWhereField:@"state" isLessThanOrEqualTo:@"IN"];
[[citiesRef queryWhereField:@"state" isEqualTo:@"CA"]
    queryWhereField:@"population" isGreaterThan:@1000000];
ViewController.m
Java
citiesRef.whereGreaterThanOrEqualTo("state", "CA")
        .whereLessThanOrEqualTo("state", "IN");
citiesRef.whereEqualTo("state", "CA")
        .whereGreaterThan("population", 1000000);
DocSnippets.java
Kotlin
citiesRef.whereGreaterThanOrEqualTo("state", "CA")
        .whereLessThanOrEqualTo("state", "IN")
citiesRef.whereEqualTo("state", "CA")
        .whereGreaterThan("population", 1000000)
DocSnippets.kt
Java
Query validQuery1 = cities.whereGreaterThanOrEqualTo("state", "CA")
    .whereLessThanOrEqualTo("state", "IN");
Query validQuery2 = cities.whereEqualTo("state", "CA")
    .whereGreaterThan("population", 1000000);
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')
cities_ref.where(u'state', u'>=', u'CA').where(u'state', u'<=', u'IN')
snippets.py
Node.js
citiesRef.where('state', '>=', 'CA').where('state', '<=', 'IN');
citiesRef.where('state', '==', 'CA').where('population', '>', 1000000);
index.js
Go
stateQuery := cities.Where("state", ">=", "CA").Where("state", "<", "IN")
populationQuery := cities.Where("state", "==", "CA").Where("population", ">", 1000000)
query.go
PHP
$rangeQuery = $citiesRef
    ->where('state', '>=', 'CA')
    ->where('state', '<=', 'IN');
range_query.php
C#
Query rangeQuery = citiesRef
    .WhereGreaterThanOrEqualTo("State", "CA")
    .WhereLessThanOrEqualTo("State", "IN");
Program.cs
Ruby
range_query = cities_ref.where("state", ">=", "CA").where("state", "<=", "IN")
query_data.rb

Inválido: filtros de intervalos em campos diferentes

Site
citiesRef.where("state", ">=", "CA").where("population", ">", 100000)
test.firestore.js
Swift
citiesRef
    .whereField("state", isGreaterThanOrEqualTo: "CA")
    .whereField("population", isGreaterThan: 1000000)
ViewController.swift
Objective-C
[[citiesRef queryWhereField:@"state" isGreaterThanOrEqualTo:@"CA"]
    queryWhereField:@"population" isGreaterThan:@1000000];
ViewController.m
Java
citiesRef.whereGreaterThanOrEqualTo("state", "CA").whereGreaterThan("population", 100000);
DocSnippets.java
Kotlin
citiesRef.whereGreaterThanOrEqualTo("state", "CA")
        .whereGreaterThan("population", 100000)
DocSnippets.kt
Java
Query invalidRangeQuery = cities.whereGreaterThanOrEqualTo("state", "CA")
    .whereGreaterThan("population", 100000);
QueryDataSnippets.java
Python
cities_ref = db.collection(u'cities')
cities_ref.where(
    u'state', u'>=', u'CA').where(u'population', u'>=', 1000000)
snippets.py
Node.js
citiesRef.where('state', '>=', 'CA').where('population', '>', 1000000);
index.js
Go
query := cities.Where("state", ">=", "CA").Where("population", ">", 1000000)
query.go
PHP
$invalidRangeQuery = $citiesRef
    ->where('state', '>=', 'CA')
    ->where('population', '>', 1000000);
invalid_range_query.php
C#
Query invalidRangeQuery = citiesRef
    .WhereGreaterThanOrEqualTo("State", "CA")
    .WhereGreaterThan("Population", 1000000);
Program.cs
Ruby
invalid_range_query = cities_ref.where("state", ">=", "CA").where("population", ">", 1_000_000)
query_data.rb

Consultas do grupo de coleções

Um grupo de coleções é composto de todos os conjuntos com o mesmo ID. Por padrão, por meio das consultas são recuperados resultados de uma única coleção no seu banco de dados. Use uma consulta do grupo de coleções para recuperar documentos de um grupo em vez de uma única coleção.

Por exemplo, é possível criar um grupo de coleções de landmarks com a adição de uma subcoleção de pontos de referência a cada cidade:

Site
var citiesRef = db.collection('cities');

var landmarks = Promise.all([
    citiesRef.doc('SF').collection('landmarks').doc().set({
        name: 'Golden Gate Bridge',
        type: 'bridge'
    }),
    citiesRef.doc('SF').collection('landmarks').doc().set({
        name: 'Legion of Honor',
        type: 'museum'
    }),
    citiesRef.doc('LA').collection('landmarks').doc().set({
        name: 'Griffith Park',
        type: 'park'
    }),
    citiesRef.doc('LA').collection('landmarks').doc().set({
        name: 'The Getty',
        type: 'museum'
    }),
    citiesRef.doc('DC').collection('landmarks').doc().set({
        name: 'Lincoln Memorial',
        type: 'memorial'
    }),
    citiesRef.doc('DC').collection('landmarks').doc().set({
        name: 'National Air and Space Museum',
        type: 'museum'
    }),
    citiesRef.doc('TOK').collection('landmarks').doc().set({
        name: 'Ueno Park',
        type: 'park'
    }),
    citiesRef.doc('TOK').collection('landmarks').doc().set({
        name: 'National Museum of Nature and Science',
        type: 'museum'
    }),
    citiesRef.doc('BJ').collection('landmarks').doc().set({
        name: 'Jingshan Park',
        type: 'park'
    }),
    citiesRef.doc('BJ').collection('landmarks').doc().set({
        name: 'Beijing Ancient Observatory',
        type: 'museum'
    })
]);
test.firestore.js
Swift
let citiesRef = db.collection("cities")

var data = ["name": "Golden Gate Bridge", "type": "bridge"]
citiesRef.document("SF").collection("landmarks").addDocument(data: data)

data = ["name": "Legion of Honor", "type": "museum"]
citiesRef.document("SF").collection("landmarks").addDocument(data: data)

data = ["name": "Griffith Park", "type": "park"]
citiesRef.document("LA").collection("landmarks").addDocument(data: data)

data = ["name": "The Getty", "type": "museum"]
citiesRef.document("LA").collection("landmarks").addDocument(data: data)

data = ["name": "Lincoln Memorial", "type": "memorial"]
citiesRef.document("DC").collection("landmarks").addDocument(data: data)

data = ["name": "National Air and Space Museum", "type": "museum"]
citiesRef.document("DC").collection("landmarks").addDocument(data: data)

data = ["name": "Ueno Park", "type": "park"]
citiesRef.document("TOK").collection("landmarks").addDocument(data: data)

data = ["name": "National Museum of Nature and Science", "type": "museum"]
citiesRef.document("TOK").collection("landmarks").addDocument(data: data)

data = ["name": "Jingshan Park", "type": "park"]
citiesRef.document("BJ").collection("landmarks").addDocument(data: data)

data = ["name": "Beijing Ancient Observatory", "type": "museum"]
citiesRef.document("BJ").collection("landmarks").addDocument(data: data)
ViewController.swift
Objective-C
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];

NSDictionary *data = @{@"name": @"Golden Gate Bridge", @"type": @"bridge"};
[[[citiesRef documentWithPath:@"SF"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Legion of Honor", @"type": @"museum"};
[[[citiesRef documentWithPath:@"SF"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Griffith Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"LA"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"The Getty", @"type": @"museum"};
[[[citiesRef documentWithPath:@"LA"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Lincoln Memorial", @"type": @"memorial"};
[[[citiesRef documentWithPath:@"DC"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"National Air and Space Museum", @"type": @"museum"};
[[[citiesRef documentWithPath:@"DC"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Ueno Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"TOK"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"National Museum of Nature and Science", @"type": @"museum"};
[[[citiesRef documentWithPath:@"TOK"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Jingshan Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"BJ"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Beijing Ancient Observatory", @"type": @"museum"};
[[[citiesRef documentWithPath:@"BJ"] collectionWithPath:@"landmarks"] addDocumentWithData:data];
ViewController.m
Java
CollectionReference citiesRef = db.collection("cities");

Map<String, Object> ggbData = new HashMap<>();
ggbData.put("name", "Golden Gate Bridge");
ggbData.put("type", "bridge");
citiesRef.document("SF").collection("landmarks").add(ggbData);

Map<String, Object> lohData = new HashMap<>();
lohData.put("name", "Legion of Honor");
lohData.put("type", "musuem");
citiesRef.document("SF").collection("landmarks").add(lohData);

Map<String, Object> gpData = new HashMap<>();
gpData.put("name", "Griffith Park");
gpData.put("type", "park");
citiesRef.document("LA").collection("landmarks").add(gpData);

Map<String, Object> tgData = new HashMap<>();
tgData.put("name", "The Getty");
tgData.put("type", "museum");
citiesRef.document("LA").collection("landmarks").add(tgData);

Map<String, Object> lmData = new HashMap<>();
lmData.put("name", "Lincoln Memorial");
lmData.put("type", "memorial");
citiesRef.document("DC").collection("landmarks").add(lmData);

Map<String, Object> nasaData = new HashMap<>();
nasaData.put("name", "National Air and Space Musuem");
nasaData.put("type", "museum");
citiesRef.document("DC").collection("landmarks").add(nasaData);

Map<String, Object> upData = new HashMap<>();
upData.put("name", "Ueno Park");
upData.put("type", "park");
citiesRef.document("TOK").collection("landmarks").add(upData);

Map<String, Object> nmData = new HashMap<>();
nmData.put("name", "National Musuem of Nature and Science");
nmData.put("type", "museum");
citiesRef.document("TOK").collection("landmarks").add(nmData);

Map<String, Object> jpData = new HashMap<>();
jpData.put("name", "Jingshan Park");
jpData.put("type", "park");
citiesRef.document("BJ").collection("landmarks").add(jpData);

Map<String, Object> baoData = new HashMap<>();
baoData.put("name", "Beijing Ancient Observatory");
baoData.put("type", "museum");
citiesRef.document("BJ").collection("landmarks").add(baoData);
DocSnippets.java
Kotlin
val citiesRef = db.collection("cities")

val ggbData = mapOf(
        "name" to "Golden Gate Bridge",
        "type" to "bridge"
)
citiesRef.document("SF").collection("landmarks").add(ggbData)

val lohData = mapOf(
        "name" to "Legion of Honor",
        "type" to "museum"
)
citiesRef.document("SF").collection("landmarks").add(lohData)

val gpData = mapOf(
        "name" to "Griffth Park",
        "type" to "park"
)
citiesRef.document("LA").collection("landmarks").add(gpData)

val tgData = mapOf(
        "name" to "The Getty",
        "type" to "museum"
)
citiesRef.document("LA").collection("landmarks").add(tgData)

val lmData = mapOf(
        "name" to "Lincoln Memorial",
        "type" to "memorial"
)
citiesRef.document("DC").collection("landmarks").add(lmData)

val nasaData = mapOf(
        "name" to "National Air and Space Museum",
        "type" to "museum"
)
citiesRef.document("DC").collection("landmarks").add(nasaData)

val upData = mapOf(
        "name" to "Ueno Park",
        "type" to "park"
)
citiesRef.document("TOK").collection("landmarks").add(upData)

val nmData = mapOf(
        "name" to "National Musuem of Nature and Science",
        "type" to "museum"
)
citiesRef.document("TOK").collection("landmarks").add(nmData)

val jpData = mapOf(
        "name" to "Jingshan Park",
        "type" to "park"
)
citiesRef.document("BJ").collection("landmarks").add(jpData)

val baoData = mapOf(
        "name" to "Beijing Ancient Observatory",
        "type" to "musuem"
)
citiesRef.document("BJ").collection("landmarks").add(baoData)
DocSnippets.kt
Java
CollectionReference cities = db.collection("cities");

final List<ApiFuture<WriteResult>> futures = Arrays.asList(
  cities.document("SF").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Golden Gate Bridge");
    put("type", "bridge");
  }}),
  cities.document("SF").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Legion of Honor");
    put("type", "museum");
  }}),
  cities.document("LA").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Griffith Park");
    put("type", "park");
  }}),
  cities.document("LA").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "The Getty");
    put("type", "museum");
  }}),
  cities.document("DC").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Lincoln Memorial");
    put("type", "memorial");
  }}),
  cities.document("DC").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "National Air and Space Museum");
    put("type", "museum");
  }}),
  cities.document("TOK").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Ueno Park");
    put("type", "park");
  }}),
  cities.document("TOK").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "National Museum of Nature and Science");
    put("type", "museum");
  }}),
  cities.document("BJ").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Jingshan Park");
    put("type", "park");
  }}),
  cities.document("BJ").collection("landmarks").document().set(new HashMap<String, String>() {{
    put("name", "Beijing Ancient Observatory");
    put("type", "museum");
  }})
);
final List<WriteResult> landmarks = ApiFutures.allAsList(futures).get();
QueryDataSnippets.java
Python
cities = db.collection(u'cities')

sf_landmarks = cities.document(u'SF').collection(u'landmarks')
sf_landmarks.document().set({
    u'name': u'Golden Gate Bridge',
    u'type': u'bridge'
})
sf_landmarks.document().set({
    u'name': u'Legion of Honor',
    u'type': u'museum'
})
la_landmarks = cities.document(u'LA').collection(u'landmarks')
la_landmarks.document().set({
    u'name': u'Griffith Park',
    u'type': u'park'
})
la_landmarks.document().set({
    u'name': u'The Getty',
    u'type': u'museum'
})
dc_landmarks = cities.document(u'DC').collection(u'landmarks')
dc_landmarks.document().set({
    u'name': u'Lincoln Memorial',
    u'type': u'memorial'
})
dc_landmarks.document().set({
    u'name': u'National Air and Space Museum',
    u'type': u'museum'
})
tok_landmarks = cities.document(u'TOK').collection(u'landmarks')
tok_landmarks.document().set({
    u'name': u'Ueno Park',
    u'type': u'park'
})
tok_landmarks.document().set({
    u'name': u'National Museum of Nature and Science',
    u'type': u'museum'
})
bj_landmarks = cities.document(u'BJ').collection(u'landmarks')
bj_landmarks.document().set({
    u'name': u'Jingshan Park',
    u'type': u'park'
})
bj_landmarks.document().set({
    u'name': u'Beijing Ancient Observatory',
    u'type': u'museum'
})
Node.js
let citiesRef = db.collection('cities');

let landmarks = Promise.all([
  citiesRef.doc('SF').collection('landmarks').doc().set({
    name: 'Golden Gate Bridge',
    type: 'bridge'
  }),
  citiesRef.doc('SF').collection('landmarks').doc().set({
    name: 'Legion of Honor',
    type: 'museum'
  }),
  citiesRef.doc('LA').collection('landmarks').doc().set({
    name: 'Griffith Park',
    type: 'park'
  }),
  citiesRef.doc('LA').collection('landmarks').doc().set({
    name: 'The Getty',
    type: 'museum'
  }),
  citiesRef.doc('DC').collection('landmarks').doc().set({
    name: 'Lincoln Memorial',
    type: 'memorial'
  }),
  citiesRef.doc('DC').collection('landmarks').doc().set({
    name: 'National Air and Space Museum',
    type: 'museum'
  }),
  citiesRef.doc('TOK').collection('landmarks').doc().set({
    name: 'Ueno Park',
    type: 'park'
  }),
  citiesRef.doc('TOK').collection('landmarks').doc().set({
    name: 'National Museum of Nature and Science',
    type: 'museum'
  }),
  citiesRef.doc('BJ').collection('landmarks').doc().set({
    name: 'Jingshan Park',
    type: 'park'
  }),
  citiesRef.doc('BJ').collection('landmarks').doc().set({
    name: 'Beijing Ancient Observatory',
    type: 'museum'
  })
]);
index.js
Go
import (
	"context"
	"fmt"

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

// collectionGroupSetup sets up a collection group to query.
func collectionGroupSetup(projectID string) error {
	ctx := context.Background()

	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("firestore.NewClient: %v", err)
	}
	defer client.Close()

	landmarks := []struct {
		city, name, t string
	}{
		{"SF", "Golden Gate Bridge", "bridge"},
		{"SF", "Legion of Honor", "museum"},
		{"LA", "Griffith Park", "park"},
		{"LA", "The Getty", "museum"},
		{"DC", "Lincoln Memorial", "memorial"},
		{"DC", "National Air and Space Museum", "museum"},
		{"TOK", "Ueno Park", "park"},
		{"TOK", "National Museum of Nature and Science", "museum"},
		{"BJ", "Jingshan Park", "park"},
		{"BJ", "Beijing Ancient Observatory", "museum"},
	}

	cities := client.Collection("cities")
	for _, l := range landmarks {
		if _, err := cities.Doc(l.city).Collection("landmarks").NewDoc().Set(ctx, map[string]string{
			"name": l.name,
			"type": l.t,
		}); err != nil {
			return fmt.Errorf("Set: %v", err)
		}
	}

	return nil
}

collection_group_setup.go
PHP
// Snippet not yet available
C#
// Snippet not yet available
Ruby
// Snippet not yet available

Podemos usar a consulta simples e a composta descritas anteriormente para consultar a subcoleção landmarks de uma cidade, mas também é possível recuperar os resultados da subcoleção de cada cidade ao mesmo tempo.

No grupo de coleções landmarks estão todos os conjuntos com o ID . Para consultá-lo, basta fazer uma consulta de grupo de coleções. Por exemplo, com esta consulta de grupo de coleções são recuperados todos os pontos de referência museum em todas as cidades:

Site
var museums = db.collectionGroup('landmarks').where('type', '==', 'museum');
museums.get().then(function (querySnapshot) {
    querySnapshot.forEach(function (doc) {
        console.log(doc.id, ' => ', doc.data());
    });
});
test.firestore.js
Swift
db.collectionGroup("landmarks").whereField("type", isEqualTo: "museum").getDocuments { (snapshot, error) in
    // ...
}
ViewController.swift
Objective-C
[[[self.db collectionGroupWithID:@"landmarks"] queryWhereField:@"type" isEqualTo:@"museum"]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
    // ...
}];
ViewController.m
Java
db.collectionGroup("landmarks").whereEqualTo("type", "museum").get()
        .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
            @Override
            public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
                // ...
            }
        });
DocSnippets.java
Kotlin
db.collectionGroup("landmarks").whereEqualTo("type", "museum").get()
        .addOnSuccessListener { queryDocumentSnapshots ->
            // ...
        }
DocSnippets.kt
Java
final Query museums = db.collectionGroup("landmarks").whereEqualTo("type", "museum");
final ApiFuture<QuerySnapshot> querySnapshot = museums.get();
for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
QueryDataSnippets.java
Python
museums = db.collection_group(u'landmarks')\
    .where(u'type', u'==', u'museum')
docs = museums.stream()
for doc in docs:
    print(u'{} => {}'.format(doc.id, doc.to_dict()))
Node.js
let museums = db.collectionGroup('landmarks').where('type', '==', 'museum');
museums.get().then(function(querySnapshot) {
  querySnapshot.forEach(function(doc) {
    console.log(doc.id, ' => ', doc.data());
  });
});
index.js
Go
import (
	"context"
	"fmt"
	"io"

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

// collectionGroupQuery runs a collection group query over the data created by
// collectionGroupSetup.
func collectionGroupQuery(w io.Writer, projectID string) error {
	ctx := context.Background()

	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("firestore.NewClient: %v", err)
	}
	defer client.Close()

	it := client.CollectionGroup("landmarks").Where("type", "==", "museum").Documents(ctx)
	for {
		doc, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%s: %s", doc.Ref.ID, doc.Data()["name"])
	}

	return nil
}

collection_group_query.go
PHP
// Snippet not yet available
C#
// Snippet not yet available
Ruby
// Snippet not yet available

Antes de usar uma consulta do grupo de coleções, é preciso criar um índice compatível com ela. Faça isso por meio de uma mensagem de erro, do console ou da Firebase CLI.

No caso de SDKs da Web e para dispositivos móveis, você também precisa criar regras que permitam consultas do grupo de coleções.

Limitações de consulta

O Cloud Firestore não aceita os tipos de consultas a seguir:

  • Consultas com filtros de intervalo em campos diferentes, conforme descrito na seção anterior.
  • Consultas com operador lógico OR. Nesse caso, crie uma consulta separada para cada condição OR e mescle os resultados da consulta no seu app.
  • Consultas com uma cláusula !=. Nesse caso, divida a consulta em duas: uma do tipo “maior que” e outra do tipo “menor que”. Por exemplo, a cláusula de consulta where("age", "!=", "30") não é aceita, mas é possível conseguir o mesmo conjunto de resultados combinando duas consultas, uma com a cláusula where("age", "<", "30") e outra com a cláusula where("age", ">", 30).