I thought I read that you can query subcollections with the new Firebase Firestore, but I don't see any examples. For example I have my Firestore setup in the following way:
Dances [collection]
danceName
Songs [collection]
songName
How would I be able to query "Find all dances where songName == 'X'"
Update 2019-05-07
Today we released collection group queries, and these allow you to query across subcollections.
So, for example in the web SDK:
db.collectionGroup('Songs')
.where('songName', '==', 'X')
.get()
This would match documents in any collection where the last part of the collection path is 'Songs'.
Your original question was about finding dances where songName == 'X', and this still isn't possible directly, however, for each Song that matched you can load its parent.
Original answer
This is a feature which does not yet exist. It's called a "collection group query" and would allow you query all songs regardless of which dance contained them. This is something we intend to support but don't have a concrete timeline on when it's coming.
The alternative structure at this point is to make songs a top-level collection and make which dance the song is a part of a property of the song.
UPDATE
Now Firestore supports array-contains
Having these documents
{danceName: 'Danca name 1', songName: ['Title1','Title2']}
{danceName: 'Danca name 2', songName: ['Title3']}
do it this way
collection("Dances")
.where("songName", "array-contains", "Title1")
.get()...
#Nelson.b.austin Since firestore does not have that yet, I suggest you to have a flat structure, meaning:
Dances = {
danceName: 'Dance name 1',
songName_Title1: true,
songName_Title2: true,
songName_Title3: false
}
Having it in that way, you can get it done:
var songTitle = 'Title1';
var dances = db.collection("Dances");
var query = dances.where("songName_"+songTitle, "==", true);
I hope this helps.
UPDATE 2019
Firestore have released Collection Group Queries. See Gil's answer above or the official Collection Group Query Documentation
Previous Answer
As stated by Gil Gilbert, it seems as if collection group queries is currently in the works. In the mean time it is probably better to use root level collections and just link between these collection using the document UID's.
For those who don't already know, Jeff Delaney has some incredible guides and resources for anyone working with Firebase (and Angular) on AngularFirebase.
Firestore NoSQL Relational Data Modeling - Here he breaks down the basics of NoSQL and Firestore DB structuring
Advanced Data Modeling With Firestore by Example - These are more advanced techniques to keep in the back of your mind. A great read for those wanting to take their Firestore skills to the next level
What if you store songs as an object instead of as a collection? Each dance as, with songs as a field: type Object (not a collection)
{
danceName: "My Dance",
songs: {
"aNameOfASong": true,
"aNameOfAnotherSong": true,
}
}
then you could query for all dances with aNameOfASong:
db.collection('Dances')
.where('songs.aNameOfASong', '==', true)
.get()
.then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
console.log(doc.id, " => ", doc.data());
});
})
.catch(function(error) {
console.log("Error getting documents: ", error);
});
NEW UPDATE July 8, 2019:
db.collectionGroup('Songs')
.where('songName', isEqualTo:'X')
.get()
I have found a solution.
Please check this.
var museums = Firestore.instance.collectionGroup('Songs').where('songName', isEqualTo: "X");
museums.getDocuments().then((querySnapshot) {
setState(() {
songCounts= querySnapshot.documents.length.toString();
});
});
And then you can see Data, Rules, Indexes, Usage tabs in your cloud firestore from console.firebase.google.com.
Finally, you should set indexes in the indexes tab.
Fill in collection ID and some field value here.
Then Select the collection group option.
Enjoy it. Thanks
You can always search like this:-
this.key$ = new BehaviorSubject(null);
return this.key$.switchMap(key =>
this.angFirestore
.collection("dances").doc("danceName").collections("songs", ref =>
ref
.where("songName", "==", X)
)
.snapshotChanges()
.map(actions => {
if (actions.toString()) {
return actions.map(a => {
const data = a.payload.doc.data() as Dance;
const id = a.payload.doc.id;
return { id, ...data };
});
} else {
return false;
}
})
);
Query limitations
Cloud Firestore does not support the following types of queries:
Queries with range filters on different fields.
Single queries across multiple collections or subcollections. Each query runs against a single collection of documents. For more
information about how your data structure affects your queries, see
Choose a Data Structure.
Logical OR queries. In this case, you should create a separate query for each OR condition and merge the query results in your app.
Queries with a != clause. In this case, you should split the query into a greater-than query and a less-than query. For example, although
the query clause where("age", "!=", "30") is not supported, you can
get the same result set by combining two queries, one with the clause
where("age", "<", "30") and one with the clause where("age", ">", 30).
I'm working with Observables here and the AngularFire wrapper but here's how I managed to do that.
It's kind of crazy, I'm still learning about observables and I possibly overdid it. But it was a nice exercise.
Some explanation (not an RxJS expert):
songId$ is an observable that will emit ids
dance$ is an observable that reads that id and then gets only the first value.
it then queries the collectionGroup of all songs to find all instances of it.
Based on the instances it traverses to the parent Dances and get their ids.
Now that we have all the Dance ids we need to query them to get their data. But I wanted it to perform well so instead of querying one by one I batch them in buckets of 10 (the maximum angular will take for an in query.
We end up with N buckets and need to do N queries on firestore to get their values.
once we do the queries on firestore we still need to actually parse the data from that.
and finally we can merge all the query results to get a single array with all the Dances in it.
type Song = {id: string, name: string};
type Dance = {id: string, name: string, songs: Song[]};
const songId$: Observable<Song> = new Observable();
const dance$ = songId$.pipe(
take(1), // Only take 1 song name
switchMap( v =>
// Query across collectionGroup to get all instances.
this.db.collectionGroup('songs', ref =>
ref.where('id', '==', v.id)).get()
),
switchMap( v => {
// map the Song to the parent Dance, return the Dance ids
const obs: string[] = [];
v.docs.forEach(docRef => {
// We invoke parent twice to go from doc->collection->doc
obs.push(docRef.ref.parent.parent.id);
});
// Because we return an array here this one emit becomes N
return obs;
}),
// Firebase IN support up to 10 values so we partition the data to query the Dances
bufferCount(10),
mergeMap( v => { // query every partition in parallel
return this.db.collection('dances', ref => {
return ref.where( firebase.firestore.FieldPath.documentId(), 'in', v);
}).get();
}),
switchMap( v => {
// Almost there now just need to extract the data from the QuerySnapshots
const obs: Dance[] = [];
v.docs.forEach(docRef => {
obs.push({
...docRef.data(),
id: docRef.id
} as Dance);
});
return of(obs);
}),
// And finally we reduce the docs fetched into a single array.
reduce((acc, value) => acc.concat(value), []),
);
const parentDances = await dance$.toPromise();
I copy pasted my code and changed the variable names to yours, not sure if there are any errors, but it worked fine for me. Let me know if you find any errors or can suggest a better way to test it with maybe some mock firestore.
var songs = []
db.collection('Dances')
.where('songs.aNameOfASong', '==', true)
.get()
.then(function(querySnapshot) {
var songLength = querySnapshot.size
var i=0;
querySnapshot.forEach(function(doc) {
songs.push(doc.data())
i ++;
if(songLength===i){
console.log(songs
}
console.log(doc.id, " => ", doc.data());
});
})
.catch(function(error) {
console.log("Error getting documents: ", error);
});
It could be better to use a flat data structure.
The docs specify the pros and cons of different data structures on this page.
Specifically about the limitations of structures with sub-collections:
You can't easily delete subcollections, or perform compound queries across subcollections.
Contrasted with the purported advantages of a flat data structure:
Root-level collections offer the most flexibility and scalability, along with powerful querying within each collection.
I stored some data using db.collection("articles").doc(); and update it using db.collection("articles").doc(postData.articleId).update(postData);. But creating new article next time, the postData.articleId is accumulated.
First, I create a doc, then update data in real time using socket.io. but I create another doc later, postData.id was accumulated.
var doc = db.collection("articles").doc();
var postData = {
author: user.email,
articleId: doc.id,
currentTime: new Date()
}
doc.set(postData);
--- get data from client code here (using socket) ---
db.collection("articles").doc(postData.articleId).update(postData); /*Update Data to postData.id.*/
The expected result is not accumulation postData.id when new data added.
(For more info: https://github.com/officialmansu/opinion-express/tree/develop)
The update() method of Cloud Firestore is specifically meant to provide partial updates (sometimes also known as patches) to an existing document.
If you want to instead replace all existing data of the document, use set(). So:
db.collection("articles").doc(postData.articleId).set(postData);
I am new to Firestore, need some help on firestore update.
I have following structure and wants to update "employee name" property. Not sure how to select and update.
Department:[
Name: Accounts
Employee:[
{Name :David,
Age :25},
{Name:Paul,
Age:27}
]
]
Here is what I was trying to do:
let depempCollectionRef = admin.firestore().collection('DepEmployee').doc('depempid')
depempCollectionRef.Department.Employee
.update({ name: 'Scott' },{merge:true})
.then(function() { console.log("Document successfully updated!"); })
Employee is just an embedded data structure in your Firestore document – so you can't address it through the reference directly. As far as Firestore is concerned, Employee is just an attribute on the Department document as Name is.
Before I propose a solution, let me point out two things:
If using update, you don't need {merge: true}. You use {merge: true} together with set to get an update-like behavior, if the document already exists.
I wouldn't use an Array of employees. It might make more sense to store the employees in their own collection in Firestore and then just list their reference IDs (= foreign keys) here. As a general rule of thumb: try to keep your data structure flat. Also use Arrays only, if you need to maintain a certain order of items.
A) If you have a separate collection for employees, updating the name is as easy as:
employeeCollection.doc('101').update({name: 'Scott'})
B) If you want to store employee data within your department document, I would still store them as a map with IDs (instead of an Array) and then access them with dot notation:
Department:[
Name: Accounts
Employees:{
101: {
Name :David,
Age :25
},
102: {
Name:Paul,
Age:27
}
}
]
depempCollectionRef.Department
.set({ ['101.name']: 'Scott' }, {merge:true})
C) And if you really want to store the data embedded in an Array, I believe you have to read and update the whole Array (not sure, if there is a better solution):
const employeesSnap = await depempCollectionRef.Department.get()
const updatedEmployees = changeNameOfScottInArray()
depempCollectionRef.Department
.update({ 'Employees': updatedEmployees })
I didn't test this code, but I hope you get the gist of it!
I'd recommend you flatten your data structure by creating a separate Employee collection and then just referencing them by their foreign key in your department (solution A).
I've got my users signing in with facebook and that gets stored in firebase auth. In index.js i've got an onCreate function that stores some facebook related data in firestore.
When i log to cloud functions console event.data.providerData I get this:
[ { displayName: 'xxxx xxxxx',
photoURL: 'https://scontent.xx.fbcdn.net/v/t1.0-1/p100x100/xxxxxxxxx_439xxx336xxxxxx.jpg?oh=bcxxxxxxxxxxx431ce&oe=xxxx4xxx3',
providerId: 'facebook.com',
uid: 'xxxxx725xxxxxx80' } ]
In my index.js file i've set this as
const providerData = event.data.providerData;
This always confuses me and i've read about it a lot.
These are my questions:
Is this a javascript object? Or a JSON object? Or a JSON array?
Does this need to be parsed? eg. JSON.parse(event.data.providerData)? What is JSON.parse actually doing?
To get access to the uid I have tried:
providerData[3]
providerData.uid
providerData["uid"]
providerData['uid']
JSON.parse(providerData) - and then all the above again
var obj = JSON.parse(providerData);
console.log( obj.uid );
I know there are plenty of posts out there re: similar topics and I think i've read a lot of them.
Thanks.
It's an array containing a JSON object at index 0.
The javascript interpreter is automatically parsing Valid JSON as a Javascript object.
Knowing that, you can now access directly the properties of your object like this:
providerData[0].displayName
providerData[0].photoURL
providerData[0].providerId
providerData[0].uid // <-- Your use case
I'm working with Angularjs and Firebase. Right now I'm new at firebase for this I'm struggling to find solutions for my issues.
Imagine I'm sorting users like this
users:{
facebook:123456789:{
blog: [{
// List of blogs
}],
following: [{
// List of users auth.ids
}]
},
facebook:123456780:{
blog: [{
// List of blogs
}],
following: [{
// List of users auth.ids
}]
}
}
And getting logged in user blog object and iterating and pushing it to the array like this
var blogRef = new Firebase(FirebaseUrl + "/users/" + authData.uid + "/blog");
var userBlog = $firebaseArray(blogRef);
var userBlogDatas = []
blogRef.limitToLast(10).on("child_added", function(snapshot) {
var snap = snapshot.val();
userBlogDatas.push(snap);
});
So far everything working fine.
But how can i get latest blogposts from feeds from following users. Right now I have some idea which represents getting user blog datas and pushing them into array. I'm not sure is it right way or not...
I also read https://github.com/firebase/firefeed/blob/master/www/js/firefeed.js code but I could not get any information for myself.
Any ideas will be really helpfull.
Thank you
There's a couple of ways to do this if I am understanding the question correctly.
One way is that instead of storing the user_id, store the user id as a key and the blog id as the value like
users
facebook:123456789
blog
// List of blogs
following
user_id_0: blog_id_x
user_id_1: blog_id_y
Then you can add an observer to each blog in the following node. You can get the path from the key/value pair. In this case Facebook:123456789 is following:
/users/user_id_0/blog/blog_id_x
/users/user_id_1/blog/blog_id_y
Another option would be to create a child node within the following node that contains two values: the user_id and blog_id.
users
facebook:123456789
blog
// List of blogs
following
follow_id_0
userid: user_id_0
blog: blog_id_0
follow_id_1
userid: user_id_0
blog: blog_id_1
In this case, facebook:123456789 is following user_id_0's blog 0 and blog 1
Note: user_id_0 and user_id_1 are actually Facebook:abcdefg users id's