删除数据

以下示例演示了如何删除文档、字段和集合。

删除文档

如需删除文档，请使用 delete() 方法：

Web

db.collection("cities").doc("DC").delete().then(function() {
    console.log("Document successfully deleted!");
}).catch(function(error) {
    console.error("Error removing document: ", error);
});
test.firestore.js

Swift

db.collection("cities").document("DC").delete() { err in
    if let err = err {
        print("Error removing document: \(err)")
    } else {
        print("Document successfully removed!")
    }
}
ViewController.swift

Objective-C

[[[self.db collectionWithPath:@"cities"] documentWithPath:@"DC"]
    deleteDocumentWithCompletion:^(NSError * _Nullable error) {
      if (error != nil) {
        NSLog(@"Error removing document: %@", error);
      } else {
        NSLog(@"Document successfully removed!");
      }
}];
ViewController.m
  

Java
Android

db.collection("cities").document("DC")
        .delete()
        .addOnSuccessListener(new OnSuccessListener<Void>() {
            @Override
            public void onSuccess(Void aVoid) {
                Log.d(TAG, "DocumentSnapshot successfully deleted!");
            }
        })
        .addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Log.w(TAG, "Error deleting document", e);
            }
        });
DocSnippets.java

Kotlin+KTX
Android

db.collection("cities").document("DC")
        .delete()
        .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully deleted!") }
        .addOnFailureListener { e -> Log.w(TAG, "Error deleting document", e) }
DocSnippets.kt

Java

// asynchronously delete a document
ApiFuture<WriteResult> writeResult = db.collection("cities").document("DC").delete();
// ...
System.out.println("Update time : " + writeResult.get().getUpdateTime());
ManageDataSnippets.java

Python

db.collection(u'cities').document(u'DC').delete()
snippets.py

C++

db->Collection("cities").Document("DC").Delete().OnCompletion(
    [](const Future<void>& future) {
      if (future.error() == Error::kErrorOk) {
        std::cout << "DocumentSnapshot successfully deleted!\n";
      } else {
        std::cout << "Error deleting document: " << future.error_message()
                  << '\n';
      }
    });
snippets.cpp
  

Node.js

const res = await db.collection('cities').doc('DC').delete();
index.js

Go

_, err := client.Collection("cities").Doc("DC").Delete(ctx)
if err != nil {
	// Handle any errors in an appropriate way, such as returning them.
	log.Printf("An error has occurred: %s", err)
}
save.go

PHP

$db->collection('cities')->document('DC')->delete();
delete_doc.php

Unity

DocumentReference cityRef = db.Collection("cities").Document("DC");
cityRef.DeleteAsync();

C#

DocumentReference cityRef = db.Collection("cities").Document("DC");
await cityRef.DeleteAsync();
Program.cs

Ruby

city_ref = firestore.doc "#{collection_path}/DC"
city_ref.delete
delete_data.rb

警告：删除文档时，其子集合不会随之删除！

删除文档时，Firestore 不会自动删除其子集合中的文档。您仍然可以通过引用访问子集合文档。例如，即使您删除位于 /mycoll/mydoc 的祖先文档，也可以访问路径为 /mycoll/mydoc/mysubcoll/mysubdoc 的文档。

不存在的祖先文档会显示在控制台中，但不会显示在查询结果和快照中。

如果要删除某个文档及其子集合中的所有文档，您必须手动操作。如需了解详情，请参阅删除集合。

删除字段

如需从文档中删除特定字段，请在更新文档时使用 FieldValue.delete() 方法：

Web

var cityRef = db.collection('cities').doc('BJ');

// Remove the 'capital' field from the document
var removeCapital = cityRef.update({
    capital: firebase.firestore.FieldValue.delete()
});
test.firestore.js

Swift

db.collection("cities").document("BJ").updateData([
    "capital": FieldValue.delete(),
]) { err in
    if let err = err {
        print("Error updating document: \(err)")
    } else {
        print("Document successfully updated")
    }
}
ViewController.swift

Objective-C

[[[self.db collectionWithPath:@"cities"] documentWithPath:@"BJ"] updateData:@{
  @"capital": [FIRFieldValue fieldValueForDelete]
} completion:^(NSError * _Nullable error) {
  if (error != nil) {
    NSLog(@"Error updating document: %@", error);
  } else {
    NSLog(@"Document successfully updated");
  }
}];
ViewController.m
  

Java
Android

DocumentReference docRef = db.collection("cities").document("BJ");

// Remove the 'capital' field from the document
Map<String,Object> updates = new HashMap<>();
updates.put("capital", FieldValue.delete());

docRef.update(updates).addOnCompleteListener(new OnCompleteListener<Void>() {
    // ...
    // ...
DocSnippets.java

Kotlin+KTX
Android

val docRef = db.collection("cities").document("BJ")

// Remove the 'capital' field from the document
val updates = hashMapOf<String, Any>(
        "capital" to FieldValue.delete()
)

docRef.update(updates).addOnCompleteListener { }
DocSnippets.kt

Java

DocumentReference docRef = db.collection("cities").document("BJ");
Map<String, Object> updates = new HashMap<>();
updates.put("capital", FieldValue.delete());
// Update and delete the "capital" field in the document
ApiFuture<WriteResult> writeResult = docRef.update(updates);
System.out.println("Update time : " + writeResult.get());
ManageDataSnippets.java

Python

city_ref = db.collection(u'cities').document(u'BJ')
city_ref.update({
    u'capital': firestore.DELETE_FIELD
})
snippets.py

C++

DocumentReference doc_ref = db->Collection("cities").Document("BJ");
doc_ref.Update({{"capital", FieldValue::Delete()}})
    .OnCompletion([](const Future<void>& future) { /*...*/ });
snippets.cpp
  

Node.js

// Get the `FieldValue` object
const FieldValue = admin.firestore.FieldValue;

// Create a document reference
const cityRef = db.collection('cities').doc('BJ');

// Remove the 'capital' field from the document
const res = await cityRef.update({
  capital: FieldValue.delete()
});
index.js

Go

_, err := client.Collection("cities").Doc("BJ").Update(ctx, []firestore.Update{
	{
		Path:  "capital",
		Value: firestore.Delete,
	},
})
if err != nil {
	// Handle any errors in an appropriate way, such as returning them.
	log.Printf("An error has occurred: %s", err)
}
save.go

PHP

$cityRef = $db->collection('cities')->document('BJ');
$cityRef->update([
    ['path' => 'capital', 'value' => FieldValue::deleteField()]
]);
delete_field.php

Unity

DocumentReference cityRef = db.Collection("cities").Document("BJ");
Dictionary<string, object> updates = new Dictionary<string, object>
{
    { "Capital", FieldValue.Delete }
};

C#

DocumentReference cityRef = db.Collection("cities").Document("BJ");
Dictionary<string, object> updates = new Dictionary<string, object>
{
    { "Capital", FieldValue.Delete }
};
await cityRef.UpdateAsync(updates);
Program.cs

Ruby

city_ref = firestore.doc "#{collection_path}/BJ"
city_ref.update capital: firestore.field_delete
delete_data.rb

删除集合

如需删除 Firestore 中的整个集合或子集合，请检索该集合或子集合中的所有文档并将其删除。如果您的集合较大，可能需要分批删除文档，以免发生内存不足的错误。重复这一过程，直到删除整个集合或子集合。

为删除集合，您需要协调不定数量的单独的删除请求。如果您需要删除整个集合，请仅从可信的服务器环境中执行此操作。虽然可以从移动/Web 客户端删除集合，但这样做会对安全和性能产生负面影响。

下面的代码段已经过简化，不涉及错误处理、安全、删除子集合或性能最大化。如需详细了解在生产环境中删除集合的一种推荐方法，请参阅删除集合与子集合。

网页

// Deleting collections from a Web client is not recommended.

Swift

// Deleting collections from an iOS client is not recommended.

Objective-C

// Deleting collections from an iOS client is not recommended.
  

Java
Android

// Deleting collections from an Android client is not recommended.

Kotlin+KTX
Android

// Deleting collections from an Android client is not recommended.

Java

/** Delete a collection in batches to avoid out-of-memory errors.
 * Batch size may be tuned based on document size (atmost 1MB) and application requirements.
 */
void deleteCollection(CollectionReference collection, int batchSize) {
  try {
    // retrieve a small batch of documents to avoid out-of-memory errors
    ApiFuture<QuerySnapshot> future = collection.limit(batchSize).get();
    int deleted = 0;
    // future.get() blocks on document retrieval
    List<QueryDocumentSnapshot> documents = future.get().getDocuments();
    for (QueryDocumentSnapshot document : documents) {
      document.getReference().delete();
      ++deleted;
    }
    if (deleted >= batchSize) {
      // retrieve and delete another batch
      deleteCollection(collection, batchSize);
    }
  } catch (Exception e) {
    System.err.println("Error deleting collection : " + e.getMessage());
  }
}
ManageDataSnippets.java

Python

def delete_collection(coll_ref, batch_size):
    docs = coll_ref.limit(batch_size).stream()
    deleted = 0

    for doc in docs:
        print(f'Deleting doc {doc.id} => {doc.to_dict()}')
        doc.reference.delete()
        deleted = deleted + 1

    if deleted >= batch_size:
        return delete_collection(coll_ref, batch_size)
snippets.py

C++

// This is not supported. Delete data using CLI as discussed below.
  

Node.js

async function deleteCollection(db, collectionPath, batchSize) {
  const collectionRef = db.collection(collectionPath);
  const query = collectionRef.orderBy('__name__').limit(batchSize);

  return new Promise((resolve, reject) => {
    deleteQueryBatch(db, query, resolve).catch(reject);
  });
}

async function deleteQueryBatch(db, query, resolve) {
  const snapshot = await query.get();

  const batchSize = snapshot.size;
  if (batchSize === 0) {
    // When there are no documents left, we are done
    resolve();
    return;
  }

  // Delete documents in a batch
  const batch = db.batch();
  snapshot.docs.forEach((doc) => {
    batch.delete(doc.ref);
  });
  await batch.commit();

  // Recurse on the next process tick, to avoid
  // exploding the stack.
  process.nextTick(() => {
    deleteQueryBatch(db, query, resolve);
  });
}
index.js

Go

func deleteCollection(ctx context.Context, client *firestore.Client,
	ref *firestore.CollectionRef, batchSize int) error {

	for {
		// Get a batch of documents
		iter := ref.Limit(batchSize).Documents(ctx)
		numDeleted := 0

		// Iterate through the documents, adding
		// a delete operation for each one to a
		// WriteBatch.
		batch := client.Batch()
		for {
			doc, err := iter.Next()
			if err == iterator.Done {
				break
			}
			if err != nil {
				return err
			}

			batch.Delete(doc.Ref)
			numDeleted++
		}

		// If there are no documents to delete,
		// the process is over.
		if numDeleted == 0 {
			return nil
		}

		_, err := batch.Commit(ctx)
		if err != nil {
			return err
		}
	}
}
save.go

PHP

function delete_collection($collectionReference, $batchSize)
{
    $documents = $collectionReference->limit($batchSize)->documents();
    while (!$documents->isEmpty()) {
        foreach ($documents as $document) {
            printf('Deleting document %s' . PHP_EOL, $document->id());
            $document->reference()->delete();
        }
        $documents = $collectionReference->limit($batchSize)->documents();
    }
}
delete_collection.php

Unity

// This is not supported. Delete data using CLI as discussed below.

C#

private static async Task DeleteCollection(CollectionReference collectionReference, int batchSize)
{
    QuerySnapshot snapshot = await collectionReference.Limit(batchSize).GetSnapshotAsync();
    IReadOnlyList<DocumentSnapshot> documents = snapshot.Documents;
    while (documents.Count > 0)
    {
        foreach (DocumentSnapshot document in documents)
        {
            Console.WriteLine("Deleting document {0}", document.Id);
            await document.Reference.DeleteAsync();
        }
        snapshot = await collectionReference.Limit(batchSize).GetSnapshotAsync();
        documents = snapshot.Documents;
    }
    Console.WriteLine("Finished deleting all documents from the collection.");
}
Program.cs

Ruby

cities_ref = firestore.col collection_path
query      = cities_ref

query.get do |document_snapshot|
  puts "Deleting document #{document_snapshot.document_id}."
  document_ref = document_snapshot.ref
  document_ref.delete
end
delete_data.rb

使用 Firebase CLI 删除数据

您还可以使用 Firebase CLI 删除文档和集合。如需删除数据，请使用以下命令：

firebase firestore:delete [options] <<path>>

使用 Console 删除数据

您可以从控制台的 Firestore 页面删除文档和集合。从控制台删除文档将删除该文档中的所有嵌套数据，包括所有子集合。