Is there a way to achieve this?
i have tried to assign the entry to a local variable but it doesn't work with crudmethods.
getData() async {
String userId = 'userId';
Firestore.instance.collection('user').document(userId).snapshots();
var snapshot;
var userDocument = snapshot.data;
String _myAddress = userDocument["address"];
return Firestore.instance
.collection('letters')
.where("source Box", isEqualTo: _myAddress)
.snapshots();
}
Yes, you should be able to use a document in the query of another document.
For this, you need to create a reference for one collection and use it in another one.
The below code is an example that you can give it a try adapting further for your case, but that I believe should help you.
// Create references to the profile and orders collections
var profilesRef = db.collection("profile");
var ordersRef = db.collection("orders");
// Create a query against the collection.
var query = ordersRef.where("username", "==", ).doc("username").get();
In the documentation Perform simple and compound queries in Cloud Firestore, there is more information and example of queries that should help you.
In addition to that, this below post from the Community can provide you some insights on how to achieve this type of query as well.
How can I get specific document data from firestore querysnapshot?
Let me know if the information helped you!
Related
How to get docs id from some matching condition?
I was able to get this to work:
Future getChat({required String userIdsArr}) async {
var docId = '';
await chat.where('User ids', isEqualTo: userIdsArr).get().then((value) {
value.docs.forEach((element) {
docId = element.id;
});
});
//print(docId);
return docId
}
this returns the correct record, however, I think this is a terrible way of quering the database because I have to fetch all the records everytime.
Is there a way to write this so that I get the doc Id of the matching condition?
Unfortunately, there is not a better way to accomplish this. When you use the where clause though, it won't fetch everything like you suspect, only records that contain the value you are querying for. I don't believe it's as expensive of a call as you might think.
I have 2 collections, one called Timeline and one called Posts. The first one is very simple, having 2 fields: 'PostId' and 'OwnerId', while the second one is a little bit more complex but it is not important for the purpose of my question.
Using 'OwnerId' and 'PostId' I can get a specified post in the collection Posts.
What I want to do is getting all the docs in timeline of a specified user, for each doc use it to get the post infos in Posts collection, and order the posts in descending timestamp, but I can't find a smart and effective way to do so.
To get all the docs of a specified user in Timeline I write:
QuerySnapshot snapshot = await timelineRef
.doc(currentUserID)
.collection('timelinePosts')
.get();
And to get a specified post from Posts collection I write:
QuerySnapshot snapshot = await postsRef
.doc(ownerId)
.collection('userPosts')
.doc(postId)
.get();
How can I mix these two to get the result I want? Thank you
There is no concept of a server-side join in Firestore, nor is there a way to filter the documents returned based on information in documents in another collection. All Firestore queries can do is evaluate the literal data in the candidate documents (through an index) and filter based on that.
So you will either have to duplicate the data to filter on in each userPosts document, or perform a so-called client-side join - with the latter being the most reasonable option for this use-case as far as I can see.
You'll end up with individual get() calls for the documents, or a bunch in in queries on the FieldPath.documentId() you get from timelinePosts, and then merge the results in your application code.
At the moment I found a solution that is not very elegant but at least is working:
QuerySnapshot snapshot = await timelineRef
.doc(widget.currentUser.userID)
.collection('timelinePosts')
.orderBy('timestamp', descending: true)
.get();
List<TimelineItem> timelineItems =
snapshot.docs.map((doc) => TimelineItem.fromDocument(doc)).toList();
List<PostWidget> postsTemp = [];
for (var element in timelineItems) {
DocumentSnapshot documentSnapshot = await postsRef
.doc(element.ownerId)
.collection('userPosts')
.doc(element.postId)
.get();
postsTemp.add(PostWidget(Post.fromDocument(documentSnapshot)));
}
I added timestamp field to my timelinePosts, created a class to contain the data from the first query, and then I did a second query based on the parameters I got on the first one for each doc.
Hopefully I'll find a more efficient solution but at the moment I use this
Can i search a Firestore DocumentID with a List<String>?
I am trying to search through my collection with some selection of documentID in a List. The List will consist of few String. Can I search through the Firestore collection using this?
This is the List:
List<String> _selectedBusStop = List<String>();
This is the code I used in finding the DocumentID based on the list that is in here.
Future <void> saveRoute(_selectedBusStop) async{
Firestore.instance.collection('markers').where('BusstopName', isEqualTo: _selectedBusStop)
.snapshots().listen((location) {
if(location.documents.isNotEmpty){
for (int i = 0; i < location.documents.length; i++){
initRoute(location.documents[i].data, location.documents[i]);
}
}
});
setState(() {
});
}
I am using where and isEqualTo or is this approach wrong? Any idea how to make it work for this part? Thank you in advance for your help.
Update:
This is how my Firestore looks like:
The List have some of the BusstopName but not all of it. I do not want to retrieve all the data from the Firestore just the one that is in the List. Sorry for causing so many misunderstanding.
Use the whereIn operator, like this:
Future <void> saveRoute(_selectedBusStop) async{
Firestore.instance.collection('markers').where('BusstopName', whereIn: _selectedBusStop)
.snapshots().listen((location) {
if(location.documents.isNotEmpty){
for (int i = 0; i < location.documents.length; i++){
initRoute(location.documents[i].data, location.documents[i]);
}
}
});
setState(() {
});
}
Assuming your documents have a unique id stored in the field BusstopName and also the documents actual id matches the content of this field, you have 2 possibilities.
(1) .where query
query data with collection("markers").where("BusstopName", "=", "yourBuststopId").
this returns a querySnapshot Object, on which you can call .size to check if there were any documents with that Id found (could be more than 1 if you have an inconsistent database).
(2) .doc query
query data with collection("markers").doc("yourBuststopId")
this returns a documentSnapshot Object, on which you can call .exist to check if the document actually exsists.
In both cases you need to do 1 query per Id, because Firestore queries only support equality and range operations. See this similar SO question. I would suggest to do the queries asynchronously, otherwise the time to execute will increase with the size of the array.
If you are concerned about costs, you only get billed for the results that actually return documents that exist.
you might also try this:
FirebaseFirestore.instance
.collection('markers')
.where('BusstopName', arrayContainsAny: ['Utar Bus Stop', 'Garden Bus Stop'])
.get()
.then(...);
Taken from the examples documentation
I'm trying to get only one document from the collection.
I have Collection named cards, in this collection I've created Documents with Auto ID, each Document have field Name. In one of the documents fild Name = Horse.
How can I retrive this document and all the fields related to it?
The problem that I've faced is that all of the documentation relay on listviews. In my case I don't have a need and use of listview.
Try this:
final colRef = Firestore.instance.collection("your_path");
final snapshot = await colRef.where("Name", isEqualTo: "Horse").limit(1).getDocuments();
final docSnapshot = snapshot.documents[0];
I´ve a role based data model on Firestore according to googles suggestion here: https://firebase.google.com/docs/firestore/solutions/role-based-access
Security rules are set up correctly and work fine. But now I´ve the problem on how to query for the roles.
This is my data model (one sample document):
id: "1234-5678-91234",
roles:
userId_1:"owner",
userId_2:"editor
title: "This is a sample document"
And this is my Firestore Query in Flutter which gets all documents for a specific user by its ID if the user has assigned the role "owner" for the document:
return firestore
.collection(path)
.where("roles.${user.firebaseUserId}", isEqualTo: "owner")
.snapshots().map((snapshot) {
return snapshot.documents.map((catalog) {
return SomeDocumentObject(...);
}).toList();
});
My problem now is, that I need some kind of "OR" clause - which does not exist as far as I know. The query above only retrieves documents for users with role "owner" but I need a query that also retrieves the document if the userId is associated with the role "editor".
I´ve tried "arrayContains:" which also doesn´t seem to work (cause it´s a map).
I´ve read about solutions with two independent queries which doesn´t sound like a good solution due to a lot of overhead.
Maybe someone of you have a hint for me? :)
Thanks & best,
Michael
Firestore doesn't currently have any logical OR operations. You'll have to perform two queries, one for each condition, and merge the results of both queries in the client app.
This is the final solution using RxDart, Observables and .combineLatest() - maybe it helps someone out there:
#override
Stream<List<Catalog>> catalogs(User user) {
// Retrieve all catalogs where user is owner
Observable<QuerySnapshot> ownerCatalogs = Observable(firestore
.collection(path)
.where("roles.${user.firebaseUserId}", isEqualTo: "owner")
.snapshots());
// Retrieve all catalogs where user is editor
Observable<QuerySnapshot> editorCatalogs = Observable(firestore
.collection(path)
.where("roles.${user.firebaseUserId}", isEqualTo: "editor")
.snapshots());
// Convert merged stream to list of catalogs
return Observable.combineLatest([ownerCatalogs, editorCatalogs],
(List<QuerySnapshot> snapshotList) {
List<Catalog> catalogs = [];
snapshotList.forEach((snapshot) {
snapshot.documents.forEach((DocumentSnapshot catalog) {
catalogs.add(Catalog(
id: catalog.documentID,
title: catalog.data['title'],
roles: catalog.data['roles'],
));
});
});
return catalogs;
}).asBroadcastStream();
}