I have a list. I need to check with field on firestore.
var ref = _db.collection('requirement')
.where('subCategory.id',arrayContains: ['8ZaGrU1kMGqxnYWBGO5R','UHtbfwoHOtdZ1rwlpjFE']);
this way is not working.
Possible with IN queries but i think the update will come late to flutter https://firebase.googleblog.com/2019/11/cloud-firestore-now-supports-in-queries.html?linkId=76644965
Updated:
https://pub.dev/packages/cloud_firestore#-changelog-tab-
0.12.11 #
Added support for in and array-contains-any query operators.
Related
I use this code to get a collection snapshot from Firestore.
firestore().collection('project').where('userID', '==', authStore.uid).onSnapshot(onResult, onError);
This returns a huge amount of data, but I only need a few fields. Is it possible to query only a specific field? For example, if I only need the projectName and the creationDate fields.
Is it possible to query only a specific field?
No, that is not possbile. A Firestore listener fires on the document level. This means that you'll always get the entire document.
For example if I only need the projectName and the creationDate fields.
You cannot only get the value of a specific set of fields. It's the entire document or nothing. If you, however, only need to read those values and nothing more, then you should consider storing them in a separate document. This practice is called denormalization, and it's a common practice when it comes to NoSQL databases.
You might also take into consideration using the Firebase Realtime Database, for the duplicated data.
I have a nested collection in firestore that I want to make a query from it.
As you can see the first collection called 'businessUsers' and the nested one called 'campaigns',
If I make a query for a field in the 'businessUsers' it's working OK:
return FirebaseFirestore.instance.collection("businessUsers").where('xxx',
isEqualTo:filterBusinessResult ).snapshots().map(_businessListFromSnapshot);
but how can I make a query to 'campaigns' collection field?
I tried
return FirebaseFirestore.instance.collection("businessUsers").doc().collection("campaigns").where('campaignCategory', isEqualTo:filterBusinessResult ).snapshots()
.map(_businessListFromSnapshot);
but it wont work.
Its important to note, that I need all the data with 'campaignCategory' == filterBusinessResult
any idea?
It depends on whether you want to query a specific user's campaigns, or the campaigns of all users together.
If you want to query the campaigns of a specific user, you need to query under their document:
FirebaseFirestore.instance
.collection("businessUsers").doc("your user ID").
.collection("campaigns")
.where('campaignCategory', isEqualTo:filterBusinessResult)
So you have to know the ID of the businessUsers document here.
If you want to query across all campaigns subcollections are once, that is known as a collection group query and would look like this:
FirebaseFirestore.instance
.collectionGroup("campaigns")
.where('campaignCategory', isEqualTo:filterBusinessResult)
The results are going to documents from the campaigns collection only, but you can look up the parent document reference for each DocumentSnapshot with docSnapshot.reference.parent.parent.
When querying something, .doc() requires the id of the document you're trying to get. So it's failing because it doesn't know which document in the businessUsers collection you're trying to fetch a subcollection on. You probably want to use a .collectionGroup() query here. They let you query all subcollections at once (see documentation here). With FlutterFire specifically, it's going to be something like:
var snapshots = FirebaseFirestore.instance.collectionGroup("campaigns")
.where("campaignCategory", isEqualTo: filterBusinessResult)
.snapshots();
I have structured my data in Firebase such that I have a collection of 'users' and each user has various fields as well as a 'skillsIndustry' Array field which contain Maps items (that have fields 'experience' and 'industry').
Now I would like to query my collection of users so that I can ask for all users that have worked in 'Airlines' with experience code of >= 1
Is this possible at all? Or do I have to create sub collections and then use Collection Group Queries?
Many thanks
No, this is not possible. You can use array-contains to query for the entire object, as explained in this SO answer, but not to query with > or <.
You could create a subcollection, but you can probably find a solution based on the duplication of the data in the same document, which is a common approach in the NoSQL world.
For example, you could have some extra fields named airlinesExperience, shippingExperience, etc. Then you use the skillsIndustry Array field when you want to display all the skills and years of experience, but you use the xxxExperience fields when you want to query.
Another possibility would be to use a map of key/value pairs like
key = "Airlines" / value = 1
key = "Shipping" / value = 3
Then you can query with:
firebase
.firestore()
.collection('users')
.where('skillsIndustry.Shipping', '>', 2)
For example, do a query where due date is today and createdby some user ?
Yes, you can query any collection or subcollection using two (or even more) fields as filters. You should take a look at the documentation.
is this a valid query for Firestore?
return firestore.collection('users')
.where('userInfo.gender', '==', "male")
.where('userInfo.yob','>=',`${data.minYear}`)
.where('userInfo.yob','<=',`${data.maxYear}`)
.orderBy('count','asc')
.limit(5)
.get()
if i want this query to be valid how do i need to structure this?
or how do i add the indexes?
It is not. If you're doing a greater-than-or-less-than search on one field, you can't then order your results by another field. You're going to have to do the yob query first, and then sort the results afterwards.
For more information, you can check out the documentation here, or this helpful video!