There are several ways to write data to Cloud Firestore:
- Set the data of a document within a collection, explicitly specifying a document identifier.
- Add a new document to a collection. In this case, Cloud Firestore automatically generates the document identifier.
- Create an empty document with an automatically generated identifier, and assign data to it later.
This guide explains how to use the set, add, or update individual documents in Cloud Firestore. If you want to write data in bulk, see Transactions and Batched Writes.
Set a document
To create or overwrite a single document, use the set()
method:
Web version 9
import { doc, setDoc } from "firebase/firestore"; // Add a new document in collection "cities" await setDoc(doc(db, "cities", "LA"), { name: "Los Angeles", state: "CA", country: "USA" });
Web version 8
// Add a new document in collection "cities" db.collection("cities").doc("LA").set({ name: "Los Angeles", state: "CA", country: "USA" }) .then(() => { console.log("Document successfully written!"); }) .catch((error) => { console.error("Error writing document: ", error); });
Swift
// Add a new document in collection "cities" db.collection("cities").document("LA").setData([ "name": "Los Angeles", "state": "CA", "country": "USA" ]) { err in if let err = err { print("Error writing document: \(err)") } else { print("Document successfully written!") } }
Objective-C
// Add a new document in collection "cities" [[[self.db collectionWithPath:@"cities"] documentWithPath:@"LA"] setData:@{ @"name": @"Los Angeles", @"state": @"CA", @"country": @"USA" } completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error writing document: %@", error); } else { NSLog(@"Document successfully written!"); } }];
Java
Map<String, Object> city = new HashMap<>(); city.put("name", "Los Angeles"); city.put("state", "CA"); city.put("country", "USA"); db.collection("cities").document("LA") .set(city) .addOnSuccessListener(new OnSuccessListener<Void>() { @Override public void onSuccess(Void aVoid) { Log.d(TAG, "DocumentSnapshot successfully written!"); } }) .addOnFailureListener(new OnFailureListener() { @Override public void onFailure(@NonNull Exception e) { Log.w(TAG, "Error writing document", e); } });
Kotlin+KTX
val city = hashMapOf( "name" to "Los Angeles", "state" to "CA", "country" to "USA" ) db.collection("cities").document("LA") .set(city) .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") } .addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) }
Dart
final city = <String, String>{ "name": "Los Angeles", "state": "CA", "country": "USA" }; db .collection("cities") .doc("LA") .set(city) .onError((e, _) => print("Error writing document: $e"));
Java
Python
Python
C++
// Add a new document in collection 'cities' db->Collection("cities") .Document("LA") .Set({{"name", FieldValue::String("Los Angeles")}, {"state", FieldValue::String("CA")}, {"country", FieldValue::String("USA")}}) .OnCompletion([](const Future<void>& future) { if (future.error() == Error::kErrorOk) { std::cout << "DocumentSnapshot successfully written!" << std::endl; } else { std::cout << "Error writing document: " << future.error_message() << std::endl; } });
Node.js
Go
PHP
$data = [ 'name' => 'Los Angeles', 'state' => 'CA', 'country' => 'USA' ]; $db->collection('samples/php/cities')->document('LA')->set($data);
Unity
DocumentReference docRef = db.Collection("cities").Document("LA"); Dictionary<string, object> city = new Dictionary<string, object> { { "Name", "Los Angeles" }, { "State", "CA" }, { "Country", "USA" } }; docRef.SetAsync(city).ContinueWithOnMainThread(task => { Debug.Log("Added data to the LA document in the cities collection."); });
C#
DocumentReference docRef = db.Collection("cities").Document("LA"); Dictionary<string, object> city = new Dictionary<string, object> { { "name", "Los Angeles" }, { "state", "CA" }, { "country", "USA" } }; await docRef.SetAsync(city);
Ruby
If the document does not exist, it will be created. If the document does exist, its contents will be overwritten with the newly provided data, unless you specify that the data should be merged into the existing document, as follows:
Web version 9
import { doc, setDoc } from "firebase/firestore"; const cityRef = doc(db, 'cities', 'BJ'); setDoc(cityRef, { capital: true }, { merge: true });
Web version 8
var cityRef = db.collection('cities').doc('BJ'); var setWithMerge = cityRef.set({ capital: true }, { merge: true });
Swift
// Update one field, creating the document if it does not exist. db.collection("cities").document("BJ").setData([ "capital": true ], merge: true)
Objective-C
// Write to the document reference, merging data with existing // if the document already exists [[[self.db collectionWithPath:@"cities"] documentWithPath:@"BJ"] setData:@{ @"capital": @YES } merge:YES completion:^(NSError * _Nullable error) { // ... }];
Java
// Update one field, creating the document if it does not already exist. Map<String, Object> data = new HashMap<>(); data.put("capital", true); db.collection("cities").document("BJ") .set(data, SetOptions.merge());
Kotlin+KTX
// Update one field, creating the document if it does not already exist. val data = hashMapOf("capital" to true) db.collection("cities").document("BJ") .set(data, SetOptions.merge())
Dart
// Update one field, creating the document if it does not already exist. final data = {"capital": true}; db.collection("cities").doc("BJ").set(data, SetOptions(merge: true));
Java
Python
Python
C++
db->Collection("cities").Document("BJ").Set( {{"capital", FieldValue::Boolean(true)}}, SetOptions::Merge());
Node.js
Go
PHP
$cityRef = $db->collection('samples/php/cities')->document('BJ'); $cityRef->set([ 'capital' => true ], ['merge' => true]);
Unity
DocumentReference docRef = db.Collection("cities").Document("LA"); Dictionary<string, object> update = new Dictionary<string, object> { { "capital", false } }; docRef.SetAsync(update, SetOptions.MergeAll);
C#
DocumentReference docRef = db.Collection("cities").Document("LA"); Dictionary<string, object> update = new Dictionary<string, object> { { "capital", false } }; await docRef.SetAsync(update, SetOptions.MergeAll);
Ruby
If you're not sure whether the document exists, pass the option to merge the new data with any existing document to avoid overwriting entire documents. For documents containing maps, note that specifying a set with a field containing an empty map will overwrite the target document's map field.
Data types
Cloud Firestore lets you write a variety of data types inside a document, including strings, booleans, numbers, dates, null, and nested arrays and objects. Cloud Firestore always stores numbers as doubles, regardless of what type of number you use in your code.
Web version 9
import { doc, setDoc, Timestamp } from "firebase/firestore"; const docData = { stringExample: "Hello world!", booleanExample: true, numberExample: 3.14159265, dateExample: Timestamp.fromDate(new Date("December 10, 1815")), arrayExample: [5, true, "hello"], nullExample: null, objectExample: { a: 5, b: { nested: "foo" } } }; await setDoc(doc(db, "data", "one"), docData);
Web version 8
var docData = { stringExample: "Hello world!", booleanExample: true, numberExample: 3.14159265, dateExample: firebase.firestore.Timestamp.fromDate(new Date("December 10, 1815")), arrayExample: [5, true, "hello"], nullExample: null, objectExample: { a: 5, b: { nested: "foo" } } }; db.collection("data").doc("one").set(docData).then(() => { console.log("Document successfully written!"); });
Swift
let docData: [String: Any] = [ "stringExample": "Hello world!", "booleanExample": true, "numberExample": 3.14159265, "dateExample": Timestamp(date: Date()), "arrayExample": [5, true, "hello"], "nullExample": NSNull(), "objectExample": [ "a": 5, "b": [ "nested": "foo" ] ] ] db.collection("data").document("one").setData(docData) { err in if let err = err { print("Error writing document: \(err)") } else { print("Document successfully written!") } }
Objective-C
NSDictionary *docData = @{ @"stringExample": @"Hello world!", @"booleanExample": @YES, @"numberExample": @3.14, @"dateExample": [FIRTimestamp timestampWithDate:[NSDate date]], @"arrayExample": @[@5, @YES, @"hello"], @"nullExample": [NSNull null], @"objectExample": @{ @"a": @5, @"b": @{ @"nested": @"foo" } } }; [[[self.db collectionWithPath:@"data"] documentWithPath:@"one"] setData:docData completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error writing document: %@", error); } else { NSLog(@"Document successfully written!"); } }];
Java
Map<String, Object> docData = new HashMap<>(); docData.put("stringExample", "Hello world!"); docData.put("booleanExample", true); docData.put("numberExample", 3.14159265); docData.put("dateExample", new Timestamp(new Date())); docData.put("listExample", Arrays.asList(1, 2, 3)); docData.put("nullExample", null); Map<String, Object> nestedData = new HashMap<>(); nestedData.put("a", 5); nestedData.put("b", true); docData.put("objectExample", nestedData); db.collection("data").document("one") .set(docData) .addOnSuccessListener(new OnSuccessListener<Void>() { @Override public void onSuccess(Void aVoid) { Log.d(TAG, "DocumentSnapshot successfully written!"); } }) .addOnFailureListener(new OnFailureListener() { @Override public void onFailure(@NonNull Exception e) { Log.w(TAG, "Error writing document", e); } });
Kotlin+KTX
val docData = hashMapOf( "stringExample" to "Hello world!", "booleanExample" to true, "numberExample" to 3.14159265, "dateExample" to Timestamp(Date()), "listExample" to arrayListOf(1, 2, 3), "nullExample" to null ) val nestedData = hashMapOf( "a" to 5, "b" to true ) docData["objectExample"] = nestedData db.collection("data").document("one") .set(docData) .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") } .addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) }
Dart
final docData = { "stringExample": "Hello world!", "booleanExample": true, "numberExample": 3.14159265, "dateExample": Timestamp.now(), "listExample": [1, 2, 3], "nullExample": null }; final nestedData = { "a": 5, "b": true, }; docData["objectExample"] = nestedData; db .collection("data") .doc("one") .set(docData) .onError((e, _) => print("Error writing document: $e"));
Java
Python
Python
C++
MapFieldValue doc_data{ {"stringExample", FieldValue::String("Hello world!")}, {"booleanExample", FieldValue::Boolean(true)}, {"numberExample", FieldValue::Double(3.14159265)}, {"dateExample", FieldValue::Timestamp(Timestamp::Now())}, {"arrayExample", FieldValue::Array({FieldValue::Integer(1), FieldValue::Integer(2), FieldValue::Integer(3)})}, {"nullExample", FieldValue::Null()}, {"objectExample", FieldValue::Map( {{"a", FieldValue::Integer(5)}, {"b", FieldValue::Map( {{"nested", FieldValue::String("foo")}})}})}, }; db->Collection("data").Document("one").Set(doc_data).OnCompletion( [](const Future<void>& future) { if (future.error() == Error::kErrorOk) { std::cout << "DocumentSnapshot successfully written!" << std::endl; } else { std::cout << "Error writing document: " << future.error_message() << std::endl; } });
Node.js
Go
PHP
$data = [ 'stringExample' => 'Hello World', 'booleanExample' => true, 'numberExample' => 3.14159265, 'dateExample' => new Timestamp(new DateTime()), 'arrayExample' => array(5, true, 'hello'), 'nullExample' => null, 'objectExample' => ['a' => 5, 'b' => true], 'documentReferenceExample' => $db->collection('samples/php/data')->document('two'), ]; $db->collection('samples/php/data')->document('one')->set($data); printf('Set multiple data-type data for the one document in the data collection.' . PHP_EOL);
Unity
DocumentReference docRef = db.Collection("data").Document("one"); Dictionary<string, object> docData = new Dictionary<string, object> { { "stringExample", "Hello World" }, { "booleanExample", false }, { "numberExample", 3.14159265 }, { "nullExample", null }, { "arrayExample", new List<object>() { 5, true, "Hello" } }, { "objectExample", new Dictionary<string, object> { { "a", 5 }, { "b", true }, } }, }; docRef.SetAsync(docData);
C#
DocumentReference docRef = db.Collection("data").Document("one"); Dictionary<string, object> docData = new Dictionary<string, object> { { "stringExample", "Hello World" }, { "booleanExample", false }, { "numberExample", 3.14159265 }, { "nullExample", null }, }; ArrayList arrayExample = new ArrayList(); arrayExample.Add(5); arrayExample.Add(true); arrayExample.Add("Hello"); docData.Add("arrayExample", arrayExample); Dictionary<string, object> objectExample = new Dictionary<string, object> { { "a", 5 }, { "b", true }, }; docData.Add("objectExample", objectExample); await docRef.SetAsync(docData);
Ruby
Custom objects
Using Map
or Dictionary
objects to represent your documents is often not
very convenient, so Cloud Firestore supports writing documents with
custom classes. Cloud Firestore converts the objects to supported data
types.
Using custom classes, you could rewrite the initial example as shown:
Web version 9
class City { constructor (name, state, country ) { this.name = name; this.state = state; this.country = country; } toString() { return this.name + ', ' + this.state + ', ' + this.country; } } // Firestore data converter const cityConverter = { toFirestore: (city) => { return { name: city.name, state: city.state, country: city.country }; }, fromFirestore: (snapshot, options) => { const data = snapshot.data(options); return new City(data.name, data.state, data.country); } };
Web version 8
class City { constructor (name, state, country ) { this.name = name; this.state = state; this.country = country; } toString() { return this.name + ', ' + this.state + ', ' + this.country; } } // Firestore data converter var cityConverter = { toFirestore: function(city) { return { name: city.name, state: city.state, country: city.country }; }, fromFirestore: function(snapshot, options){ const data = snapshot.data(options); return new City(data.name, data.state, data.country); } };
Swift
public struct City: Codable { let name: String let state: String? let country: String? let isCapital: Bool? let population: Int64? enum CodingKeys: String, CodingKey { case name case state case country case isCapital = "capital" case population } }
Objective-C
// This isn't supported in Objective-C.
Java
Each custom class must have a public constructor that takes no arguments. In addition, the class must include a public getter for each property.
public class City { private String name; private String state; private String country; private boolean capital; private long population; private List<String> regions; public City() {} public City(String name, String state, String country, boolean capital, long population, List<String> regions) { // ... } public String getName() { return name; } public String getState() { return state; } public String getCountry() { return country; } public boolean isCapital() { return capital; } public long getPopulation() { return population; } public List<String> getRegions() { return regions; } }
Kotlin+KTX
data class City( val name: String? = null, val state: String? = null, val country: String? = null, @field:JvmField // use this annotation if your Boolean field is prefixed with 'is' val isCapital: Boolean? = null, val population: Long? = null, val regions: List<String>? = null )
Dart
class City { final String? name; final String? state; final String? country; final bool? capital; final int? population; final List<String>? regions; City({ this.name, this.state, this.country, this.capital, this.population, this.regions, }); factory City.fromFirestore( DocumentSnapshot<Map<String, dynamic>> snapshot, SnapshotOptions? options, ) { final data = snapshot.data() as Map<String, dynamic>; return City( name: data['name'], state: data['state'], country: data['country'], capital: data['capital'], population: data['population'], regions: data['regions'] as List<String>, ); } Map<String, dynamic> toFirestore() { return { if (name != null) "name": name, if (state != null) "state": state, if (country != null) "country": country, if (capital != null) "capital": capital, if (population != null) "population": population, if (regions != null) "regions": regions, }; } }
Java
Python
Python
C++
// This is not yet supported.
Node.js
// Node.js uses JavaScript objects
Go
PHP
// This isn't supported in PHP
Unity
[FirestoreData] public class City { [FirestoreProperty] public string Name { get; set; } [FirestoreProperty] public string State { get; set; } [FirestoreProperty] public string Country { get; set; } [FirestoreProperty] public bool Capital { get; set; } [FirestoreProperty] public long Population { get; set; } }
C#
[FirestoreData] public class City { [FirestoreProperty] public string Name { get; set; } [FirestoreProperty] public string State { get; set; } [FirestoreProperty] public string Country { get; set; } [FirestoreProperty] public bool Capital { get; set; } [FirestoreProperty] public long Population { get; set; } }
Ruby
// This isn't supported in Ruby
Web version 9
import { doc, setDoc } from "firebase/firestore"; // Set with cityConverter const ref = doc(db, "cities", "LA").withConverter(cityConverter); await setDoc(ref, new City("Los Angeles", "CA", "USA"));
Web version 8
// Set with cityConverter db.collection("cities").doc("LA") .withConverter(cityConverter) .set(new City("Los Angeles", "CA", "USA"));
Swift
let city = City(name: "Los Angeles", state: "CA", country: "USA", isCapital: false, population: 5000000) do { try db.collection("cities").document("LA").setData(from: city) } catch let error { print("Error writing city to Firestore: \(error)") }
Objective-C
// This isn't supported in Objective-C.
Java
City city = new City("Los Angeles", "CA", "USA", false, 5000000L, Arrays.asList("west_coast", "sorcal")); db.collection("cities").document("LA").set(city);
Kotlin+KTX
val city = City("Los Angeles", "CA", "USA", false, 5000000L, listOf("west_coast", "socal")) db.collection("cities").document("LA").set(city)
Dart
final city = City( name: "Los Angeles", state: "CA", country: "USA", capital: false, population: 5000000, regions: ["west_coast", "socal"], ); final docRef = db .collection("cities") .withConverter( fromFirestore: City.fromFirestore, toFirestore: (City city, options) => city.toFirestore(), ) .doc("LA"); await docRef.set(city);
Java
Python
Python
C++
// This is not yet supported.
Node.js
// Node.js uses JavaScript objects
Go
PHP
// This isn't supported in PHP.
Unity
DocumentReference docRef = db.Collection("cities").Document("LA"); City city = new City { Name = "Los Angeles", State = "CA", Country = "USA", Capital = false, Population = 3900000L }; docRef.SetAsync(city);
C#
DocumentReference docRef = db.Collection("cities").Document("LA"); City city = new City { Name = "Los Angeles", State = "CA", Country = "USA", Capital = false, Population = 3900000L }; await docRef.SetAsync(city);
Ruby
// This isn't supported in Ruby.
Add a document
When you use set()
to create a document, you must specify an ID for the
document to create. For example:
Web version 9
import { doc, setDoc } from "firebase/firestore"; await setDoc(doc(db, "cities", "new-city-id"), data);
Web version 8
db.collection("cities").doc("new-city-id").set(data);
Swift
db.collection("cities").document("new-city-id").setData(data)
Objective-C
[[[self.db collectionWithPath:@"cities"] documentWithPath:@"new-city-id"] setData:data];
Java
db.collection("cities").document("new-city-id").set(data);
Kotlin+KTX
db.collection("cities").document("new-city-id").set(data)
Dart
db.collection("cities").doc("new-city-id").set({"name": "Chicago"});
Java
Python
Python
C++
db->Collection("cities").Document("SF").Set({/*some data*/});
Node.js
Go
PHP
$db->collection('samples/php/cities')->document('new-city-id')->set($data);
Unity
db.Collection("cities").Document("new-city-id").SetAsync(city);
C#
await db.Collection("cities").Document("new-city-id").SetAsync(city);
Ruby
But sometimes there isn't a meaningful ID for the document, and it's more
convenient to let Cloud Firestore auto-generate an ID for you. You can do
this by calling add()
:
Web version 9
import { collection, addDoc } from "firebase/firestore"; // Add a new document with a generated id. const docRef = await addDoc(collection(db, "cities"), { name: "Tokyo", country: "Japan" }); console.log("Document written with ID: ", docRef.id);
Web version 8
// Add a new document with a generated id. db.collection("cities").add({ name: "Tokyo", country: "Japan" }) .then((docRef) => { console.log("Document written with ID: ", docRef.id); }) .catch((error) => { console.error("Error adding document: ", error); });
Swift
// Add a new document with a generated id. var ref: DocumentReference? = nil ref = db.collection("cities").addDocument(data: [ "name": "Tokyo", "country": "Japan" ]) { err in if let err = err { print("Error adding document: \(err)") } else { print("Document added with ID: \(ref!.documentID)") } }
Objective-C
// Add a new document with a generated id. __block FIRDocumentReference *ref = [[self.db collectionWithPath:@"cities"] addDocumentWithData:@{ @"name": @"Tokyo", @"country": @"Japan" } completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error adding document: %@", error); } else { NSLog(@"Document added with ID: %@", ref.documentID); } }];
Java
// Add a new document with a generated id. Map<String, Object> data = new HashMap<>(); data.put("name", "Tokyo"); data.put("country", "Japan"); db.collection("cities") .add(data) .addOnSuccessListener(new OnSuccessListener<DocumentReference>() { @Override public void onSuccess(DocumentReference documentReference) { Log.d(TAG, "DocumentSnapshot written with ID: " + documentReference.getId()); } }) .addOnFailureListener(new OnFailureListener() { @Override public void onFailure(@NonNull Exception e) { Log.w(TAG, "Error adding document", e); } });
Kotlin+KTX
// Add a new document with a generated id. val data = hashMapOf( "name" to "Tokyo", "country" to "Japan" ) db.collection("cities") .add(data) .addOnSuccessListener { documentReference -> Log.d(TAG, "DocumentSnapshot written with ID: ${documentReference.id}") } .addOnFailureListener { e -> Log.w(TAG, "Error adding document", e) }
Dart
// Add a new document with a generated id. final data = {"name": "Tokyo", "country": "Japan"}; db.collection("cities").add(data).then((documentSnapshot) => print("Added Data with ID: ${documentSnapshot.id}"));
Java
Python
Python
C++
db->Collection("cities").Add({/*some data*/});
Node.js
Go
PHP
$data = [ 'name' => 'Tokyo', 'country' => 'Japan' ]; $addedDocRef = $db->collection('samples/php/cities')->add($data); printf('Added document with ID: %s' . PHP_EOL, $addedDocRef->id());
Unity
Dictionary<string, object> city = new Dictionary<string, object> { { "Name", "Tokyo" }, { "Country", "Japan" } }; db.Collection("cities").AddAsync(city).ContinueWithOnMainThread(task => { DocumentReference addedDocRef = task.Result; Debug.Log(String.Format("Added document with ID: {0}.", addedDocRef.Id)); });
C#
Dictionary<string, object> city = new Dictionary<string, object> { { "Name", "Tokyo" }, { "Country", "Japan" } }; DocumentReference addedDocRef = await db.Collection("cities").AddAsync(city); Console.WriteLine("Added document with ID: {0}.", addedDocRef.Id);
Ruby
In some cases, it can be useful to create a document reference with an
auto-generated ID, then use the reference later. For this use case, you can call
doc()
:
Web version 9
import { collection, doc, setDoc } from "firebase/firestore"; // Add a new document with a generated id const newCityRef = doc(collection(db, "cities")); // later... await setDoc(newCityRef, data);
Web version 8
// Add a new document with a generated id. var newCityRef = db.collection("cities").doc(); // later... newCityRef.set(data);
Swift
let newCityRef = db.collection("cities").document() // later... newCityRef.setData([ // ... ])
Objective-C
FIRDocumentReference *newCityRef = [[self.db collectionWithPath:@"cities"] documentWithAutoID]; // later... [newCityRef setData:@{ /* ... */ }];
Java
Map<String, Object> data = new HashMap<>(); DocumentReference newCityRef = db.collection("cities").document(); // Later... newCityRef.set(data);
Kotlin+KTX
val data = HashMap<String, Any>() val newCityRef = db.collection("cities").document() // Later... newCityRef.set(data)
Dart
// Add a new document with a generated id. final data = <String, dynamic>{}; final newCityRef = db.collection("cities").doc(); // Later... newCityRef.set(data);
Java
Python
Python
C++
DocumentReference new_city_ref = db->Collection("cities").Document();
Node.js
Go
PHP
$addedDocRef = $db->collection('samples/php/cities')->newDocument(); printf('Added document with ID: %s' . PHP_EOL, $addedDocRef->id()); $addedDocRef->set($data);
Unity
DocumentReference addedDocRef = db.Collection("cities").Document(); Debug.Log(String.Format("Added document with ID: {0}.", addedDocRef.Id)); addedDocRef.SetAsync(city).ContinueWithOnMainThread(task => { Debug.Log(String.Format( "Added data to the {0} document in the cities collection.", addedDocRef.Id)); });
C#
DocumentReference addedDocRef = db.Collection("cities").Document(); Console.WriteLine("Added document with ID: {0}.", addedDocRef.Id); await addedDocRef.SetAsync(city);
Ruby
Behind the scenes, .add(...)
and .doc().set(...)
are completely
equivalent, so you can use whichever is more convenient.
Update a document
To update some fields of a document without overwriting the entire document, use
the update()
method:
Web version 9
import { doc, updateDoc } from "firebase/firestore"; const washingtonRef = doc(db, "cities", "DC"); // Set the "capital" field of the city 'DC' await updateDoc(washingtonRef, { capital: true });
Web version 8
var washingtonRef = db.collection("cities").doc("DC"); // Set the "capital" field of the city 'DC' return washingtonRef.update({ capital: true }) .then(() => { console.log("Document successfully updated!"); }) .catch((error) => { // The document probably doesn't exist. console.error("Error updating document: ", error); });
Swift
let washingtonRef = db.collection("cities").document("DC") // Set the "capital" field of the city 'DC' washingtonRef.updateData([ "capital": true ]) { err in if let err = err { print("Error updating document: \(err)") } else { print("Document successfully updated") } }
Objective-C
FIRDocumentReference *washingtonRef = [[self.db collectionWithPath:@"cities"] documentWithPath:@"DC"]; // Set the "capital" field of the city [washingtonRef updateData:@{ @"capital": @YES } completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error updating document: %@", error); } else { NSLog(@"Document successfully updated"); } }];
Java
DocumentReference washingtonRef = db.collection("cities").document("DC"); // Set the "isCapital" field of the city 'DC' washingtonRef .update("capital", true) .addOnSuccessListener(new OnSuccessListener<Void>() { @Override public void onSuccess(Void aVoid) { Log.d(TAG, "DocumentSnapshot successfully updated!"); } }) .addOnFailureListener(new OnFailureListener() { @Override public void onFailure(@NonNull Exception e) { Log.w(TAG, "Error updating document", e); } });
Kotlin+KTX
val washingtonRef = db.collection("cities").document("DC") // Set the "isCapital" field of the city 'DC' washingtonRef .update("capital", true) .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully updated!") } .addOnFailureListener { e -> Log.w(TAG, "Error updating document", e) }
Dart
final washingtonRef = db.collection("cites").doc("DC"); washingtonRef.update({"capital": true}).then( (value) => print("DocumentSnapshot successfully updated!"), onError: (e) => print("Error updating document $e"));
Java
Python
Python
C++
DocumentReference washington_ref = db->Collection("cities").Document("DC"); // Set the "capital" field of the city "DC". washington_ref.Update({{"capital", FieldValue::Boolean(true)}});
Node.js
Go
PHP
$cityRef = $db->collection('samples/php/cities')->document('DC'); $cityRef->update([ ['path' => 'capital', 'value' => true] ]);
Unity
DocumentReference cityRef = db.Collection("cities").Document("new-city-id"); Dictionary<string, object> updates = new Dictionary<string, object> { { "Capital", false } }; cityRef.UpdateAsync(updates).ContinueWithOnMainThread(task => { Debug.Log( "Updated the Capital field of the new-city-id document in the cities collection."); }); // You can also update a single field with: cityRef.UpdateAsync("Capital", false);
C#
DocumentReference cityRef = db.Collection("cities").Document("new-city-id"); Dictionary<string, object> updates = new Dictionary<string, object> { { "Capital", false } }; await cityRef.UpdateAsync(updates); // You can also update a single field with: await cityRef.UpdateAsync("Capital", false);
Ruby
Server Timestamp
You can set a field in your document to a server timestamp which tracks when the server receives the update.
Web version 9
import { updateDoc, serverTimestamp } from "firebase/firestore"; const docRef = doc(db, 'objects', 'some-id'); // Update the timestamp field with the value from the server const updateTimestamp = await updateDoc(docRef, { timestamp: serverTimestamp() });
Web version 8
var docRef = db.collection('objects').doc('some-id'); // Update the timestamp field with the value from the server var updateTimestamp = docRef.update({ timestamp: firebase.firestore.FieldValue.serverTimestamp() });
Swift
db.collection("objects").document("some-id").updateData([ "lastUpdated": FieldValue.serverTimestamp(), ]) { err in if let err = err { print("Error updating document: \(err)") } else { print("Document successfully updated") } }
Objective-C
[[[self.db collectionWithPath:@"objects"] documentWithPath:@"some-id"] updateData:@{ @"lastUpdated": [FIRFieldValue fieldValueForServerTimestamp] } completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error updating document: %@", error); } else { NSLog(@"Document successfully updated"); } }];
Java
// If you're using custom Java objects in Android, add an @ServerTimestamp // annotation to a Date field for your custom object classes. This indicates // that the Date field should be treated as a server timestamp by the object mapper. DocumentReference docRef = db.collection("objects").document("some-id"); // Update the timestamp field with the value from the server Map<String,Object> updates = new HashMap<>(); updates.put("timestamp", FieldValue.serverTimestamp()); docRef.update(updates).addOnCompleteListener(new OnCompleteListener<Void>() { // ... // ...
Kotlin+KTX
// If you're using custom Kotlin objects in Android, add an @ServerTimestamp // annotation to a Date field for your custom object classes. This indicates // that the Date field should be treated as a server timestamp by the object mapper. val docRef = db.collection("objects").document("some-id") // Update the timestamp field with the value from the server val updates = hashMapOf<String, Any>( "timestamp" to FieldValue.serverTimestamp() ) docRef.update(updates).addOnCompleteListener { }
Dart
final docRef = db.collection("objects").doc("some-id"); final updates = <String, dynamic>{ "timestamp": FieldValue.serverTimestamp(), }; docRef.update(updates).then( (value) => print("DocumentSnapshot successfully updated!"), onError: (e) => print("Error updating document $e"));
Java
Python
Python
C++
DocumentReference doc_ref = db->Collection("objects").Document("some-id"); doc_ref.Update({{"timestamp", FieldValue::ServerTimestamp()}}) .OnCompletion([](const Future<void>& future) { // ... });
Node.js
Go
PHP
$docRef = $db->collection('samples/php/objects')->document('some-id'); $docRef->update([ ['path' => 'timestamp', 'value' => FieldValue::serverTimestamp()] ]);
Unity
DocumentReference cityRef = db.Collection("cities").Document("new-city-id"); cityRef.UpdateAsync("Timestamp", FieldValue.ServerTimestamp) .ContinueWithOnMainThread(task => { Debug.Log( "Updated the Timestamp field of the new-city-id document in the cities " + "collection."); });
C#
DocumentReference cityRef = db.Collection("cities").Document("new-city-id"); await cityRef.UpdateAsync("Timestamp", Timestamp.GetCurrentTimestamp());
Ruby
When updating multiple timestamp fields inside of a transaction, each field receives the same server timestamp value.
Update fields in nested objects
If your document contains nested objects, you can use "dot notation" to
reference nested fields within the document when you call update()
:
Web version 9
import { doc, setDoc, updateDoc } from "firebase/firestore"; // Create an initial document to update. const frankDocRef = doc(db, "users", "frank"); await setDoc(frankDocRef, { name: "Frank", favorites: { food: "Pizza", color: "Blue", subject: "recess" }, age: 12 }); // To update age and favorite color: await updateDoc(frankDocRef, { "age": 13, "favorites.color": "Red" });
Web version 8
// Create an initial document to update. var frankDocRef = db.collection("users").doc("frank"); frankDocRef.set({ name: "Frank", favorites: { food: "Pizza", color: "Blue", subject: "recess" }, age: 12 }); // To update age and favorite color: db.collection("users").doc("frank").update({ "age": 13, "favorites.color": "Red" }) .then(() => { console.log("Document successfully updated!"); });
Swift
// Create an initial document to update. let frankDocRef = db.collection("users").document("frank") frankDocRef.setData([ "name": "Frank", "favorites": [ "food": "Pizza", "color": "Blue", "subject": "recess" ], "age": 12 ]) // To update age and favorite color: db.collection("users").document("frank").updateData([ "age": 13, "favorites.color": "Red" ]) { err in if let err = err { print("Error updating document: \(err)") } else { print("Document successfully updated") } }
Objective-C
// Create an initial document to update. FIRDocumentReference *frankDocRef = [[self.db collectionWithPath:@"users"] documentWithPath:@"frank"]; [frankDocRef setData:@{ @"name": @"Frank", @"favorites": @{ @"food": @"Pizza", @"color": @"Blue", @"subject": @"recess" }, @"age": @12 }]; // To update age and favorite color: [frankDocRef updateData:@{ @"age": @13, @"favorites.color": @"Red", } completion:^(NSError * _Nullable error) { if (error != nil) { NSLog(@"Error updating document: %@", error); } else { NSLog(@"Document successfully updated"); } }];
Java
// Assume the document contains: // { // name: "Frank", // favorites: { food: "Pizza", color: "Blue", subject: "recess" } // age: 12 // } // // To update age and favorite color: db.collection("users").document("frank") .update( "age", 13, "favorites.color", "Red" );
Kotlin+KTX
// Assume the document contains: // { // name: "Frank", // favorites: { food: "Pizza", color: "Blue", subject: "recess" } // age: 12 // } // // To update age and favorite color: db.collection("users").document("frank") .update(mapOf( "age" to 13, "favorites.color" to "Red" ))
Dart
// Assume the document contains: // { // name: "Frank", // favorites: { food: "Pizza", color: "Blue", subject: "recess" } // age: 12 // } db .collection("users") .doc("frank") .update({"age": 13, "favorites.color": "Red"});
Java
Python
Python
C++
// Assume the document contains: // { // name: "Frank", // favorites: { food: "Pizza", color: "Blue", subject: "recess" } // age: 12 // } // // To update age and favorite color: db->Collection("users").Document("frank").Update({ {"age", FieldValue::Integer(13)}, {"favorites.color", FieldValue::String("red")}, });
Node.js
Go
PHP
// Create an initial document to update $frankRef = $db->collection('samples/php/users')->document('frank'); $frankRef->set([ 'first' => 'Frank', 'last' => 'Franklin', 'favorites' => ['food' => 'Pizza', 'color' => 'Blue', 'subject' => 'Recess'], 'age' => 12 ]); // Update age and favorite color $frankRef->update([ ['path' => 'age', 'value' => 13], ['path' => 'favorites.color', 'value' => 'Red'] ]);
Unity
DocumentReference frankDocRef = db.Collection("users").Document("frank"); Dictionary<string, object> initialData = new Dictionary<string, object> { { "Name", "Frank" }, { "Age", 12 } }; Dictionary<string, object> favorites = new Dictionary<string, object> { { "Food", "Pizza" }, { "Color", "Blue" }, { "Subject", "Recess" }, }; initialData.Add("Favorites", favorites); frankDocRef.SetAsync(initialData).ContinueWithOnMainThread(task => { // Update age and favorite color Dictionary<string, object> updates = new Dictionary<string, object> { { "Age", 13 }, { "Favorites.Color", "Red" }, }; // Asynchronously update the document return frankDocRef.UpdateAsync(updates); }).ContinueWithOnMainThread(task => { Debug.Log( "Updated the age and favorite color fields of the Frank document in " + "the users collection."); });
C#
DocumentReference frankDocRef = db.Collection("users").Document("frank"); Dictionary<string, object> initialData = new Dictionary<string, object> { { "Name", "Frank" }, { "Age", 12 } }; Dictionary<string, object> favorites = new Dictionary<string, object> { { "Food", "Pizza" }, { "Color", "Blue" }, { "Subject", "Recess" }, }; initialData.Add("Favorites", favorites); await frankDocRef.SetAsync(initialData); // Update age and favorite color Dictionary<string, object> updates = new Dictionary<string, object> { { "Age", 13 }, { "Favorites.Color", "Red" }, }; // Asynchronously update the document await frankDocRef.UpdateAsync(updates);
Ruby
Dot notation allows you to update a single nested field without overwriting other nested field. If you update a nested field without dot notation, you will overwrite the entire map field, for example:
Web
// Create our initial doc db.collection("users").doc("frank").set({ name: "Frank", favorites: { food: "Pizza", color: "Blue", subject: "Recess" }, age: 12 }).then(function() { console.log("Frank created"); }); // Update the doc without using dot notation. // Notice the map value for favorites. db.collection("users").doc("frank").update({ favorites: { food: "Ice Cream" } }).then(function() { console.log("Frank food updated"); }); /* Ending State, favorite.color and favorite.subject are no longer present: /users /frank { name: "Frank", favorites: { food: "Ice Cream", }, age: 12 } */
Update elements in an array
If your document contains an array field, you can use arrayUnion()
and
arrayRemove()
to add and remove elements. arrayUnion()
adds elements to an
array but only elements not already present. arrayRemove()
removes all
instances of each given element.
Web version 9
import { doc, updateDoc, arrayUnion, arrayRemove } from "firebase/firestore"; const washingtonRef = doc(db, "cities", "DC"); // Atomically add a new region to the "regions" array field. await updateDoc(washingtonRef, { regions: arrayUnion("greater_virginia") }); // Atomically remove a region from the "regions" array field. await updateDoc(washingtonRef, { regions: arrayRemove("east_coast") });
Web version 8
var washingtonRef = db.collection("cities").doc("DC"); // Atomically add a new region to the "regions" array field. washingtonRef.update({ regions: firebase.firestore.FieldValue.arrayUnion("greater_virginia") }); // Atomically remove a region from the "regions" array field. washingtonRef.update({ regions: firebase.firestore.FieldValue.arrayRemove("east_coast") });
Swift
let washingtonRef = db.collection("cities").document("DC") // Atomically add a new region to the "regions" array field. washingtonRef.updateData([ "regions": FieldValue.arrayUnion(["greater_virginia"]) ]) // Atomically remove a region from the "regions" array field. washingtonRef.updateData([ "regions": FieldValue.arrayRemove(["east_coast"]) ])
Objective-C
FIRDocumentReference *washingtonRef = [[self.db collectionWithPath:@"cities"] documentWithPath:@"DC"]; // Atomically add a new region to the "regions" array field. [washingtonRef updateData:@{ @"regions": [FIRFieldValue fieldValueForArrayUnion:@[@"greater_virginia"]] }]; // Atomically remove a new region to the "regions" array field. [washingtonRef updateData:@{ @"regions": [FIRFieldValue fieldValueForArrayRemove:@[@"east_coast"]] }];
Java
DocumentReference washingtonRef = db.collection("cities").document("DC"); // Atomically add a new region to the "regions" array field. washingtonRef.update("regions", FieldValue.arrayUnion("greater_virginia")); // Atomically remove a region from the "regions" array field. washingtonRef.update("regions", FieldValue.arrayRemove("east_coast"));
Kotlin+KTX
val washingtonRef = db.collection("cities").document("DC") // Atomically add a new region to the "regions" array field. washingtonRef.update("regions", FieldValue.arrayUnion("greater_virginia")) // Atomically remove a region from the "regions" array field. washingtonRef.update("regions", FieldValue.arrayRemove("east_coast"))
Dart
final washingtonRef = db.collection("cities").doc("DC"); // Atomically add a new region to the "regions" array field. washingtonRef.update({ "regions": FieldValue.arrayUnion(["greater_virginia"]), }); // Atomically remove a region from the "regions" array field. washingtonRef.update({ "regions": FieldValue.arrayRemove(["east_coast"]), });
Java
Python
Python
C++
// This is not yet supported.
Node.js
Go
// Not supported yet
PHP
$cityRef = $db->collection('samples/php/cities')->document('DC'); // Atomically add a new region to the "regions" array field. $cityRef->update([ ['path' => 'regions', 'value' => FieldValue::arrayUnion(['greater_virginia'])] ]); // Atomically remove a region from the "regions" array field. $cityRef->update([ ['path' => 'regions', 'value' => FieldValue::arrayRemove(['east_coast'])] ]);
Unity
// This is not yet supported in the Unity SDK
C#
DocumentReference washingtonRef = db.Collection("cities").Document("DC"); // Atomically add a new region to the "regions" array field. await washingtonRef.UpdateAsync("Regions", FieldValue.ArrayUnion("greater_virginia")); // Atomically remove a region from the "regions" array field. await washingtonRef.UpdateAsync("Regions", FieldValue.ArrayRemove("east_coast"));
Ruby
// Not supported yet
Increment a numeric value
You can increment or decrement a numeric field value as shown in the following example. An increment operation increases or decreases the current value of a field by the given amount.
Web version 9
import { doc, updateDoc, increment } from "firebase/firestore"; const washingtonRef = doc(db, "cities", "DC"); // Atomically increment the population of the city by 50. await updateDoc(washingtonRef, { population: increment(50) });
Web version 8
var washingtonRef = db.collection('cities').doc('DC'); // Atomically increment the population of the city by 50. washingtonRef.update({ population: firebase.firestore.FieldValue.increment(50) });
Swift
let washingtonRef = db.collection("cities").document("DC") // Atomically increment the population of the city by 50. // Note that increment() with no arguments increments by 1. washingtonRef.updateData([ "population": FieldValue.increment(Int64(50)) ])
Objective-C
FIRDocumentReference *washingtonRef = [[self.db collectionWithPath:@"cities"] documentWithPath:@"DC"]; // Atomically increment the population of the city by 50. // Note that increment() with no arguments increments by 1. [washingtonRef updateData:@{ @"population": [FIRFieldValue fieldValueForIntegerIncrement:50] }];
Java
DocumentReference washingtonRef = db.collection("cities").document("DC"); // Atomically increment the population of the city by 50. washingtonRef.update("population", FieldValue.increment(50));
Kotlin+KTX
val washingtonRef = db.collection("cities").document("DC") // Atomically increment the population of the city by 50. washingtonRef.update("population", FieldValue.increment(50))
Dart
var washingtonRef = db.collection('cities').doc('DC'); // Atomically increment the population of the city by 50. washingtonRef.update( {"population": FieldValue.increment(50)}, );
Java
Python
Python
C++
// This is not yet supported.
Node.js
Go
PHP
$cityRef = $db->collection('samples/php/cities')->document('DC'); // Atomically increment the population of the city by 50. $cityRef->update([ ['path' => 'regions', 'value' => FieldValue::increment(50)] ]);
Unity
// This is not yet supported in the Unity SDK.
C#
DocumentReference washingtonRef = db.Collection("cities").Document("DC"); // Atomically increment the population of the city by 50. await washingtonRef.UpdateAsync("Regions", FieldValue.Increment(50));
Ruby
Increment operations are useful for implementing counters, but keep in mind that you can update a single document only once per second. If you need to update your counter above this rate, see the Distributed counters page.