When I go to delete a document from the Firestore console, I get the following message:
"This will permanently delete all data at this location, including all nested data."
However, the Firestore documentation reads: "Deleting a document does not delete the documents in its subcollections"
Can someone clarify this relationship for me?
If I delete a document from the Firestore console, it appears to remove all subcollections and nested data. If it doesn't, how can I delete said sub collections since I can no longer see them?
The console will do exactly what it says - delete the document and all of the subcollections organized under it.
The client APIs will not. If you delete a document using the standard delete() method on a document reference, it will not delete anything organized under it.
Related
I am aware of how to delete sub collections when a parent collection is deleted programmatically however I can't find any documentation on what happens when you delete a parent collection from the console manually.
Follow up question:
Is there a way to check for undeleted sub collections?
I assume these use up storage.
I just tested what happens in the Firebase console when you delete a collection, and it shows this dialog:
So it looks like deleting a collection in the console also deletes any subcollections under it.
So this is possible:
const docSnapshot = await firebase.firestore().collection("SOME_COL").doc("SOME_DOC").get();
console.log(docSnapshot.exists);
But it "downloads" the whole document just to check if it exists. And I'm currently working with some havier documents and I have a script where I just need to know if they exist, but I don't need to download them at that time.
Is there a way to check if a document exist without .get() and avoid downloading the document data?
It seems you are using the JavaScript SDK. With this SDK there isn't any way to only get a subset of the fields of a document.
One of the possible solutions is to maintain another collection with documents that have the same IDs than the main collection documents but which only hold a very small dummy field. You could use a set of Cloud Functions to synchronise the two collections (Documents creation/deletion).
On the other hand, with the Firestore REST API, it is possible, with the get method, to define a DocumentMask which defines a "set of field paths on a document" and is "used to restrict a get operation on a document to a subset of its fields". Depending on your exact use case, this can be an interesting and easier solution.
When using the Firebase console it is possible to see all documents and collections, even subcollections where the path has "documents" that do not exist.
This is illustrated in the picture included here, and as stated in the docs and on the screenshot as well. These documents won't appear in queries or snapshots. So how does the console find these nested subcollections, when a query does not return them?
Is it possible, somehow, to list these documents. Since the console can do it, it seems there must be a way.
And if it is possible to find these documents, is it possible to create a query that fetches all the documents that are non-existant but limited to those that have a nested subcollection? (Since the set of all non-existant documents would be infinite)
The Admin SDK provides a listDocuments method with this description:
The document references returned may include references to "missing
documents", i.e. document locations that have no document present but
which contain subcollections with documents. Attempting to read such a
document reference (e.g. via .get() or .onSnapshot()) will return a
DocumentSnapshot whose .exists property is false.
Combining this with the example for listing subcollections, you could do something like the following:
// Admin SDK only
let collectionRef = firestore.collection('col');
return collectionRef.listDocuments().then(documentRefs => {
return firestore.getAll(documentRefs);
}).then(documentSnapshots => {
documentSnapshots.forEach(doc => {
if( !doc.exists ) {
console.log(`Found missing document: ${documentSnapshot.id}, getting subcollections`);
doc.getCollections().then(collections => {
collections.forEach(collection => {
console.log('Found subcollection with id:', collection.id);
});
});
}
});
});
Note that the Firebase CLI uses a different approach. Via the REST API, it queries all documents below a given path, without having to know their specific location first. You can see how this works in the recursive delete code here.
Is it possible to create a query that fetches all these subcollections that are nested under a document that does not exist.
Queries in Cloud Firestore are shallow, which means they only get documents from the collection that the query is run against. There is no way in Cloud Firestore to get documents from a top-level collection and other collections or subcollections in a single query. Firestore doesn't support queries across different collections in one go. A single query may only use properties of documents in a single collection or subcollection.
So in your case, even if one document does not exist (does not contain any properties), you can still query a collection that lives beneath it. With other words, you can query the queue subcollection that exist within -LFNX ... 7UjS document but you cannot query all queue subcollection within all documents. You can query only one subcollection at a time.
Edit:
According to your comment:
I want to find collections that are nested under documents that do not exist.
There is no way to find collections because you cannot query across different collections. You can only query against one. The simplest solution I can think of is to check if a document within your items collection doesn't exist (has no properties) and then create a query (items -> documentId -> queue), and check if has any results.
Edit2:
The Firebase Console is telling you through those document ids shown in italics that those documents just does not exist. Those documents do not exist because you didn't create them at all. What you did do, was only to create a subcollection under a document that never existed in the first place. With other words, it merely "reserves" an id for a document in that collection and then creates a subcollection under it. Typically, you should only create subcollections of documents that actually do exist but this is how it looks like when the document doesn't exist.
In Cloud Firestore documents and subcollections don't work like filesystem files and directories you're used. If you create a subcollection under a document, it doesn't implicitly create any parent documents. Subcollections are not tied in any way to a parent document. With other words, there is no physical document at that location but there is other data under the location.
In Firebase console those document ids are diplayed so you can navigate down the tree and get the subcollections and documents that exist beneath it. But in the same time the console is warning you that those document does not exist, by displaying their ids in italics. So you cannot display or use them because of the simple fact that there is no data beneath it. If you want to correct that, you have to write at least a property that can hold a value. In that way, those documents will hold some data so you can do whatever you want.
P.S. In Cloud Firestore, if you delete a document, its subcollections will continue to exist and this is because of the exact same reason I mentioned above.
Excuse me,
I'm working on my code about making a Document Firestore that could be delete, this is how my Firestore Database looks like :
Firestore Data Structure
I'd like to delete the Auto-ID Document after the Collection "X-MIPA.6". So, I followed the previous solution about "Firebase Cloud Firestore get auto-id of newly created document", so here is my code looks like :
My Code
But, when I tested, my app force closed and show me this Error :
The Error
How is it possible? How can I fix it?
I want to delete the Document based on the Auto-ID Document on my Firestore Database.
Thanks!
I'm using Firebase Cloud Firestore and can't figure out how to access documents without knowing the specific path. The database structure is users/{user id}/favourites/{favourite id}. There are no fields in users/{user id} only subcollections. Knowing the user id, i can get the favourites for the user, but I can't get a list of users to get everyone's favourites. Here is the code I am trying (Java admin SDK):
db.collection("users").get().get()
which results in an empty Iterable with no DocumentSnapshots.
How can I get a list of the most popular favourites?
EDIT: I've discovered I can get a list of users with no fields if I add a field. Even if I delete it later, it still appears as a document in the collection.
EDIT2: I've discovered that I can create an empty document, so I'm just doing that for now. As a one-off, I can get a list of all users from firebase auth and look up which ones have a favourites collection and just set those to empty documents.