I´m trying to get data from Firebase depending on the name and city from object.
My firebase tree looks like this:
MYAPP
Object:
- 12837291ß2837(a random ID):
"name": "test"
"city": "Hong Kong"
- 12382133193u2:
"name": "test"
"city": "Paris"
- 2137829128738:
"name": "test2"
"city": "Frankfurt"
So for example i just want to get the Object where the name is "test" and the city is "Hong Kong".
i tried sth like this but i dont get any Data:
let ref = FIRDatabase.database().referenceFromURL("https://myRef")
ref.queryOrderedByChild("Object").queryEqualToValue("test").observeEventType(.ChildAdded) { (snapshot) in
print(snapshot)
}
I also added rules in Firebase like :
".indexOn": "Object"
Two main problems:
your query doesn't match your data structure
you can only filter on one property.
Your query doesn't match your data structure
To sort/filter you first specify the property that you want to filter on and then the filtering operation. Since the value you specify is from the name property, the correct query is:
let ref = FIRDatabase.database().referenceFromURL("https://myRef")
let query = ref.queryOrderedByChild("name").queryEqualToValue("test")
query.observeEventType(.ChildAdded) { (snapshot) in
print(snapshot)
}
You can only filter on one property
Firebase Database only supports ordering/querying on a single properties. See Query based on multiple where clauses in firebase.
Related
I currently have a data structure like this in Firebase Cloud Firestore
Database
+ ProductInventories (collection)
+ productId1 (document)
+ variantName (collection)
+ [auto-ID] (document)
+ location: "Paris"
+ count: 1334
How would I make a structuredQuery in POST to get the count for location `Paris'?
Intuitively it might have been a POST to https://firestore.googleapis.com/v1/projects/projectName/databases/(default)/documents/ProductInventories/productId1:runQuery with the following JSON
{
"structuredQuery": {
"from": [
{
"collectionId": "variantName",
"allDescendants": true
}
],
"where": {
"fieldFilter": {
"field": {
"fieldPath": "location"
},
"op": "EQUAL",
"value": {
"stringValue": "Paris"
}
}
}
}
}
With this I get error collection group queries are only allowed at the root parent, which means I need to make the POST to https://firestore.googleapis.com/v1/projects/projectName/databases/(default)/documents:runQuery instead. This however means I'll need to create a collection group index exemption for each variant (variantName) I have for each productId.
Seems like I would be better off to have below variantName collection level, the location as the name of the document, and I can then access the count directly without making a query. But seems to me the point of NoSQL was that I could be less careful about how I structure the data, so I'm wondering if there's a way for me to make the query as is with the current data structure.
Using collection names that are not known ahead of time is usually an anti-pattern in Firestore. And what you get is one of the reasons for that: you need to be able to create a collection group query across documents in multiple collections, you need to be able to define an index on the collection name - and that requires that you know those some time during development.
As usual, when using NoSQL databases, you can modify/augment your data structure to allow the use-case. For example, if you create a single subcollection for all variants, you can give that collection a fixed name, and search for paris and $variantName in there. This collection can either be a replacement of your current $variantName collections, or an addition to it.
have you tried something like this?
fb.firestore().collection('ProductInventories')
.doc('productId1')
.collection('variantName')
.where('location', '==', 'Paris')
.get()
.then(res=>{
res.data().docs.forEach((product, i)=>{
console.log('item ' + i + ': ' + product.count);
})
});
So this is the structure of my Firebase DB right now, I am using the Firebase REST API:
"company": {
company1_id {
id: company_id,
userId: userid,
name: name
//someotherstuff
}
company2_id {
id: company_id,
userId: userid,
name: name,
//someotherstuff
}
}
Soo, right now I am getting the companies belonging to one user by calling :
"firebasedbname.firebaseio.com/company.json?orderBy="userId"&equalTo=userId"
This works perfectly fine and gets the corresponding data, but now I want it to order the companies alphabetically by name, and then i try this:
"firebasedbname.firebaseio.com/company.json?orderBy="name"&equalTo=userId"
But this time, it returns no data! Even though i have added .indexOn: "name" to the company node.Any help will be aprreciated.
As explained in the doc, if you want to filter data you need to first "specify how you want your data to be filtered using the orderBy parameter", and then you need to "combine orderBy with any of the other five parameters: limitToFirst, limitToLast, startAt, endAt, and equalTo".
So if you added "an .indexOn: "name" to the company node", it means that you intend to query as follows:
https://xxxx.firebaseio.com/company.json?orderBy="name"&equalTo="companyName"
You cannot order by (company) name and filter on userId.
If you want to get all the companies corresponding to a specific user and order them by the company name, you will need to use ?orderBy="userId"&equalTo=userId" and do the sorting in the client/application calling the REST API.
We are experiencing an issue in when writing queries for Cosmos Document DB and we want to create a new document property and use it in an ORDER BY clause
If, for example, we had a set of documents like:
{
"Name": "Geoff",
"Company": "Acme"
},
{
"Name": "Bob",
"Company": "Bob Inc"
}
...and we write a query like SELECT * FROM c ORDER BY c.Name this works fine and returns both documents
However, if we were to add a new document with an additional property:
{
"Name": "Geoff",
"Company": "Acme"
},
{
"Name": "Bob",
"Company": "Bob Inc"
},
{
"Name": "Sarah",
"Company": "My Company Ltd",
"Title": "President"
}
...and we write a query like SELECT * FROM c ORDER BY c.Title it will only return the document for Sarah and excludes the 2 without a Title property.
This means that the ORDER BY clause is behaving like a filter rather than just a sort, which seems unexpected.
It seems that all document schemas are likely to add properties over time. Unless we go back and add these properties to all existing document records in the container then we can never use them in an ORDER BY clause without excluding records.
Does anyone have a solution to allow the ORDER BY to only effect the Sort order of the result set?
Currently, ORDER BY works off of indexed properties, and missing values are not included in the result of a query using ORDER BY.
As a workaround, you could do two queries and combine the results:
The current query you're doing, with ORDER BY, returning all documents containing the Title property, ordered
A second query, returning all documents that don't have Title defined.
The second query would look something like:
SELECT * FROM c
WHERE NOT IS_DEFINED(c.Title)
Also note that, according to this note within the EF Core repo issue list, behavior is a bit different when using compound indexes (where documents with missing properties are returned).
This question already has answers here:
Firestore - Nested query
(2 answers)
Closed 2 years ago.
I want to store data in following format:
{
"chatName": "Football",
"chatMembers":
[
{
"userId": "nSWnbKwL6GW9fqIQKREZENTdVyq2",
"name": "Niklas"
},
{
"userId": "V3QONGrVegQBnnINYHzXtnG1kXu1",
"name": "Timo"
},
]
}
My goal is to get all chats, where the signed in user with a userId is in the chatMembers list. If the userId of the signed in user is not in the chatMembers property, then that chat should be ignored. Is this possible?
If this is not possible, how can i achive this with subcollections?
My development language is dart, but you can also post solutions in other languages.
My current attempt is this, but this is not working:
_firestore.collection(collectionName).where("chatMembers.userId", isEqualTo: userId).snapshots()
Since August 2018 there is the new array_contains operator which allows filtering based on array values. The doc is here: https://firebase.google.com/docs/firestore/query-data/queries#array_membership
It works very well with arrays of string. However, I think it is not possible to query for a specific property of an object stored in the array. One workaround is to query for the entire object, as follows (in Javascript). Of course this may not be feasible in every situation....
var db = firebase.firestore();
var query = db.collection('chatDocs').where("chatMembers", "array-contains", { userId: "xyz", userName: "abc" });
Renaud Tarnec's, which complete, doesn't work in every case. Situations where only one or not all of the fields are known won't return the expected documents. However, by restructuring the data in the document, a query can be made to work where only one field is known, like a user identifier (uid).
Here's the data structure inside one of the document:
{
"members": {
"user4": {
"active": true,
"userName": "King Edward III",
"avatar": "www.photos.gov/animeGirl5.png"
},
"user7": {
"active": true,
"userName": "Dave K.",
"avatar": "www.photos.gov/gunsAmericanFlag.png"
}
}
Here's the query:
uid = 'user4';
collectionQuery = collectionReference.where(`members.${uid}.active`,"==", true);
In this example, "user4" represents a user who may or may not be in a group. This will return all documents in the collection where the uid "user4" is an active member. This works by only needing to know the UID of the member and works without needing to know their name or avatar uri ahead of time.
I am trying to use the Firebase orderByChild() function per the documentation example but the queries are not coming back filtered or sorted.
Here is the sample data structure:
"notifications": {
"001": {
"member_id": "abc123",
"created_at": 1424357680681,
"new": true,
"first_name": "Jon",
"last_name": "Snow",
"message": "likes your photo"
},
"002": {
"member_id": "abc456",
"created_at": 1424357680681,
"new": true,
"first_name": "Clark",
"last_name": "Kent",
"message": "likes your comment"
}
}
When a user logs in, I want to query the notifications hash for only the notifications with a member_id that matches the current user's id.
I have tried both versions with and without the "child_added".
Option A:
ref.orderByChild("member_id").equalTo(memberId);
Option B:
ref.orderByChild("member_id").equalTo(memberId)
.on("child_added", function(data) {
console.log("new child id = " + data.key());
});
When I query the notifications hash, the query returns an array of all of the notifications. They are neither limited to the member_id of the current user, nor sorted by member_id. (I can delete the member_id key entirely and the notification will still be returned).
I can always filter the returned array by member_id in-app, but I would really like to get the query working per the documentation.
Any help is appreciated!
I found the problem!
I was under the impression that you could add the query modifiers in place.
I was doing:
ref.orderByChild("member_id").equalTo(memberId);
var sync = $firebase(ref);
It should actually be:
var sync = $firebase(ref.orderByChild("member_id").equalTo(memberId));
Most likely your memberId variable is a number, while you're storing the corresponding value as a string.
If you store numbers as a string, this query won't give any results:
ref.orderByChild("member_id").equalTo(456)
But this one will:
ref.orderByChild("member_id").equalTo('456')
The easiest fix in your snippet of code is coercing the memberId to a string like this:
ref.orderByChild("member_id").equalTo(''+memberId)
See this fiddle for a working sample: http://jsfiddle.net/695rf0vy/