데이터 삭제

다음 예시에서는 문서, 필드, 컬렉션을 삭제하는 방법을 보여줍니다.

문서 삭제

문서를 삭제하려면 delete() 메서드를 사용합니다.

웹
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
자바
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
자바
// 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 "cities/DC"
city_ref.delete
delete_data.rb

문서를 삭제해도 Firestore는 하위 컬렉션 내 문서를 자동으로 삭제하지 않습니다. 따라서 참조를 통해 하위 컬렉션 문서에 액세스할 수 있습니다. 예를 들어 /mycoll/mydoc에 상위 문서가 없어도 /mycoll/mydoc/mysubcoll/mysubdoc 경로에 있는 문서에 액세스할 수 있습니다.

존재하지 않는 상위 문서가 Console에 나타나는 경우에도 쿼리나 스냅샷에는 표시되지 않습니다.

문서를 삭제할 때 하위 컬렉션의 문서까지 삭제하려면 수동으로 삭제해야 합니다. 자세한 내용은 컬렉션 삭제를 참조하세요.

필드 삭제

문서에서 특정 필드를 삭제하려면 문서를 업데이트할 때 FieldValue.delete() 메서드를 사용합니다.

웹
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
자바
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
자바
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 "cities/BJ"
city_ref.update capital: firestore.field_delete
delete_data.rb

컬렉션 삭제

Firestore에서 전체 컬렉션 또는 하위 컬렉션을 삭제하려면 컬렉션 또는 하위 컬렉션에 포함된 모든 문서를 검색하여 삭제합니다. 컬렉션 규모가 큰 경우 문서를 조금씩 나누어 삭제하면 메모리 부족 오류를 방지할 수 있습니다. 전체 컬렉션 또는 하위 컬렉션이 삭제될 때까지 이 과정을 반복하세요.

컬렉션을 삭제하려면 제한되지 않은 개별 삭제 요청 수를 조정해야 합니다. 전체 컬렉션을 삭제하려면 신뢰할 수 있는 서버 환경에서만 삭제하세요. 모바일 또는 웹 클라이언트에서도 컬렉션을 삭제할 수 있지만, 이 경우 보안 및 성능에 부정적인 영향을 미칩니다.

아래의 스니펫은 다소 단순화되어 있으므로 오류 처리, 보안, 하위 컬렉션 삭제 또는 성능 극대화에 대해서는 다루지 않습니다. 프로덕션 환경에서 컬렉션을 삭제하는 한 가지 추천 방법에 대한 자세한 내용은 컬렉션 및 하위 컬렉션 삭제를 참조하세요.

웹
// 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.
자바
Android
// Deleting collections from an Android client is not recommended.
Kotlin+KTX
Android
// Deleting collections from an Android client is not recommended.
자바
/** 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 "cities"
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

Firebase CLI를 사용한 데이터 삭제

Firebase CLI를 사용해 문서 및 컬렉션을 삭제할 수도 있습니다. 데이터를 삭제하려면 다음 명령어를 사용하세요.

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

Console을 사용하여 데이터 삭제

Console의 Firestore 페이지에서 문서 및 컬렉션을 삭제할 수 있습니다. Console에서 문서를 삭제하면 하위 컬렉션을 포함하여 해당 문서의 중첩된 데이터가 모두 삭제됩니다.