This question already has answers here:
Firebase android : make username unique
(4 answers)
Closed 5 years ago.
The problem I can't seem to find a straight answer to is how can I do a query on this list in the Firebase database by some field (a username in my case) to find the associated key for that user given that username is guaranteed to be a unique value.
I've read through the documentation on queries, but it looks like all of them need a key in some shape or form is that really the case? And if it is how is this normally avoided?
Thanks a million below is how my DB is designed.
Right now, in my database there is a list of user objects:
Database
-users
-{SomeUniqueKey}
-data: "some data"
-username: "user1"
-usernameThisUserIsFollowing: "user2"
+{SomeOtherUniqueKey}
You may use equalTo.
Reference: https://firebase.google.com/docs/database/
Related
This question already has answers here:
Can Firestore update multiple documents matching a condition, using one query?
(8 answers)
Closed 2 years ago.
I have created a chat app. In the app there is a collection named Chat and in it there are documents. Each document is a message that was sent and it contains fields such as Message, SentTime, IsButton.
Once something happens in the app (someone clicks a button), I had like to change in all of my documents at that chat the value of IsButton from False to True.
The data looks as follows:
Is there a way to change all of the Field values in one hit instead of using a loop?
I saw there is something called Batch however I'm not sure if it is limited to a maximum 500 updates.
Thank you
The two approaches you've found are pretty much the way to update a bunch of document.
You can:
either update each document individually, which is not nearly as slow as you may think.
or you can update the documents in one of more batches.
Having to update many documents with the same value may be a sign that you should reconsider your data structure. For example, maybe you can store the IsButton in a single, separate document that all clients then read/listen to.
This question already has answers here:
Firebase Android - startAt() and endAt() not working correctly?
(2 answers)
Closed 3 years ago.
I have objects named "trips" saved in the firebase database, which can uniquely identify using seasonCode and TripCode combination.
Now I want to retrieve all the trips which include a particular seasonCode (ex: trips with seasonCode="SeasonCose1"). but need to extract data set chunk wise. (let's say 10 trips at a time)
FirebaseDatabase.getInstance(firebaseApp).getReference("resources").child("trips").orderByChild("seasonCode").equalTo("seasonCode1").limitToFirst(10)
I figured this query returns first 10 trips wich seasonCode="SeasonCode1". if I have last retrieved "Trip" object, how can I retrieve the next 10 trips with seasonCode="seasonCode1"?
Finally found a solution. I can get that through wildcard queries.
Firebase Android - startAt() and endAt() not working correctly?
This question already has answers here:
Google Firestore - How to get several documents by multiple ids in one round-trip?
(17 answers)
Closed 4 years ago.
I have below FireStore data
And I have a list specialUsers which is defined as
val specialUsers = arrayOf("stark#gmail.com", "lannester#gmail.com")
So I want to get collections which are in the specialUsers, something like
collection("users").whereIn(specialUsers)
But, couldn't find any documentation related to this. How can I perform above intention in Firestore?
As he says here in 6:19
There is still no way for the database to automatically grab specific user name and profile for each review as I requesting them. I would need to make separate database request for every single review I get to fetch this information and that's bad. so If we wont to automatically include information about who rote a particular review we will need to copy sample of the user profile to the particular review and this is the way (to brake data Normalization) specifically in could FireStore.
This question already has an answer here:
How to query a Firestore collection using a property from a step deeper with Kotlin? [duplicate]
(1 answer)
Closed 4 years ago.
I am new to Firestore cloud and I am trying to learn about it.
I am trying to build a project and I am stuck at one point.
My Firestore database looks like this:
enter image description here
enter image description here
I have a Groups collection that has "Users List" Sub-collection" where I have "timestamp" and "user_id".
When I created a group I grabbed the user_id of the "user" that creates a group and added that in "Users List".
Now I am looking to retrieve all the "Groups"(groupName) that the "CurrentUser" is involved in, and I am having hard time to figure it out because I found that NoSQL databases are very different from SQL databases.
Would be great if someone can shed a light on this matter.
Thank you
I'm not sure about this, but I think your best bet is to add some field to collect group that each user involve in "Users" Collection using array or object to collect it since Firestore can collect array or object.
But TBH, I not sure this is the best, but it is the best I can think rightnow. Because with these you only need to query 1 time for each user that you want to get usergroup and it help you to not use lots of query to get usergroups for each user. But it will couse you some additional size. But it still fine since Firestore costing is base on both query and size for this case. Little(?) additional data is better than waste lots of query to get usergroup for only one user.
This question already has answers here:
How to get userID by user Email Firebase android?
(6 answers)
Closed 5 years ago.
I am trying to know if a user exists in Firebase (Email/Password Authentication) y only knowing the display name.
I am doing this is Android (Java).
Thank you so much!
There is no built-in support in Firebase Authentication to look up users by their display name. Given the loose definition of the meaning of the display name, it would be of limited use. Display names can't be required to be unique, since it's just a value that says how the user wants to be addressed: "When you show something from/to me, show this name next to it".
Many developers end up allowing their users to pick a username/nickname, which they then do require to be unique. If that approach make sense for your use-case too, I recommend reading some of these questions about how to accomplish this with the use of the Firebase Realtime Database:
Firebase android : make username unique
Enforcing unique usernames with Firebase simplelogin
Firebase query if child of child contains a value (a more general explanation of uniqueness in the Firebase Realtime Database)
How do you prevent duplicate user properties in Firebase?