I am currently working on a mobile app on React and I am having trouble understanding how to save a field from fire store that is an array.
Since I can't post images my database structure is all strings such as username, first name, etc but I have a field called follow list that is an array.
What I want to do is save the usernames from the following list into an array to later search fire store for the username's in the array, this is basically what I want to do so I can render my app's social Feed. I do know that I can probably create another subcollection and write something familiar to what I did to search for users but that was a QuerySnapShot which was overall documents not a specific one and I also know firebase creates an ID for arrays and it increases as the array gets bigger.
I do not want to end up making two more subcollections one for followers and following which I think not ideal right? My current approach is this
export const fetchUserFollowing = async (username) => {
const ref = firebase.firestore().collection('users').doc(username)
let results = []
ref
.get()
.then( doc => {
let data = doc.data()
results = data
})
.catch((err) => {
return 'an error has occurred ', err
})
}
From what I understand is that a DocumentSnapShot .get() function returns an object but what I want is to store follow list into results and then return that but I am not sure how to manipulate the object return to just give me follow List which is an array
https://rnfirebase.io/docs/v5.x.x/firestore/reference/DocumentSnapshot
link to docs
Related
Hey guys I try to get data from a document which has a Field value Name and a subcollection named kurzwaffensub but for my project I need to do a collectionGroup query and after that I need the Name value of each document which matches the query from the subcollection.
So let me explain.
First I need to do a collectionGroup query of the documents from the subcollection based on their two parameter kurzHersteller and kurzModell which I marked in green at the picture.
After that I get all Documents of every Subcollection which match the query.
And as you can see the blue document uid is the same uid as in the fieldvalue of every document of the subcollection.
And my goal is to get the red marked fieldvalue of the documents of the main collection after the group query of the subcollection.
But I only want to receive the Names of the documents which match the requirments of the query .
So in this Case i need the Name Felix Sturms because he has a document in his subcollection marked in yellow
which match the Search for kurzHersteller : Andere and kurzKaliber : Andere
I dont know if this is possible or if I need to structure my data in another way. Im a beginner with firebase firestore so perhabs you can help me.
const [test, setTest] = useState([]);
const HEuKA = query(kurzRef,where("kurzHersteller", "==", `${kurzHersteller}` ), where('kurzKaliber' , '==', `${kurzKaliber}`));
const handleClick = async () => {
...blablabla
...
} else if (kurzHersteller && kurzKaliber) {
const modell = await getDocs(HeuKa);
modell.forEach((doc) => {
// doc.data() is never undefined for query doc snapshots
setTest(doc.id, " => ", doc.data());
});
} else { alert('Bitte etwas eingeben')}
}
So thats the first operation after I receive the array of the documents of the subcollection which match the query , i need another operation to get the corresponding documents from the parent collection which contain the information about the Name of the users which have a document in the subcollection which match the values kurzHersteller: Andere and kurzModell: Andere of this example.
Once you get the QuerySnapshot from your collection group query, you can loop over every document and then access the parent document using .parent property present on the DocumentReference of each document. Try running the following code after your first query:
const modell = await getDocs(HeuKa);
const data = [];
for (const doc of modell.docs) {
const parentDoc = await getDoc(doc.ref.parent.parent);
const { Name } = parentDoc.data();
data.push({
...doc.data(),
Name,
});
}
Firestore reads/queries return documents from a single collection, or with collection group queries from all collections with the same name. There is no way in Firestore to include data from the parent document in the same read/query.
The two options you have are:
Read the parent document for any result you get from the subcollection.
Duplicate the necessary information from the parent document in each document in the subcollection.
While #1 is the most common option for people who are new to Firestore (and NoSQL databases in general), as you get more experienced with Firestore you'll often find yourself using #2 more often too.
I think a more robust way, where you don't depend on the structure, is to get the document from 'uid' field you have on each document you get back from the query'. Even better would be to change this field to type "reference", in which case you can just do (assuming you create a field called customerReference as a replacement for uid):
modell.forEach((doc) => {
const customerDoc = await doc.data().customerReference.get();
const name = customerDoc.data().Name;
Im trying to make friends system but in invite accept i have to delete invite of a guy in his list but i cant do it without the key.
How do i get the snapshot key by value (in this case uid) in database?
Firebase Realtime Database queries work on single path, and then order/filter on a value at a fixed path under each direct child node. In your case, if you know whether the user is active or pending, you can find a specific value with:
const ref = firebase.database().ref("friends");
const query = ref.child("active").orderByValue().equalTo("JrvFaTDGV6TnkZq6uGMNICxwGwo2")
const results = query.get();
results.forEach((snapshot) => {
console.log(`Found value ${snapshot.val()} under key ${snapshot.key}`)
})
There is no way to perform the same query across both active and pending nodes at the same time, so you will either have to perform a separate query for each of those, or change your data model to have a single flat list of users. In that case you'll likely store the status and UID for each user as a child property, and use orderByChild("uid").
Also note that using push IDs as keys seems an antipattern here, as my guess is that each UID should only have one status. A better data model for this is:
friends: {
"JrvFaTDGV6TnkZq6uGMNICxwGwo2": {
status: "active"
}
}
I want to clean some records of a firestore database. I have a function that receives the records I would like to keep, I check in all the records if id is not in the docsToKeep:firebase documents argument.
I use a foreach for all the records, and I user filter to find the matching id as shown in the working snippet below:
async function checkForNotifClean(docsToKeep:firebase.firestore.QuerySnapshot<firebase.firestore.DocumentData>) {
const db = firebase.firestore();
const notifCollection = db.collection('notifications')
const allData = await notifCollection.get();
allData.docs.forEach(doc => {
const filtered = docsToKeep.docs.filter(entry => entry.id === doc.id);
const needsErase = filtered.length === 0;
if (needsErase) {
const id = doc.id;
notifCollection.doc(id).delete();
}
})
}
Is there a cleaner way to erase all the documents that are not in docsToKeep ? Would be kind of function that get all the objects that are not in both arrays and delete those. I would be happy on improvements on the javascript side to filter out the records to delete, and in the firebase side, improvements regarding the chance of deleting some set of records at once instead of looping through all and deleting each.
To delete (or write to) a document in Firestore you need to know the complete path to that document, including its document ID. If you don't have the IDs of the documents to delete, then your only option is to determine those IDs as you're doing now.
It does lead to the question how docsToKeep is populated though. My guess it that the user already selects some documents from a full list. If that's the case, might you be able to pass the inverted list: docsToDelete?
I have setup a Firebase Firestore Database and would like to filter it for a certain field value in a document.
I have a collection called "PRD" with thousands of documents where all contain the same fields. One of these fields a Document contains is a GTIN Number (String). I am receiving this Number from a Bar Code (called data), and would like to retrieve the Medication Name (called DSCRD, a different Field in all these Documents) using the GTIN Number scanned.
I am having difficulties with retrieving the Value from the Firebase and the documentation doesn't seem to get me any further. I have tried various retrieval methods. At the moment the code for retrieval looks like this:
import { dbh } from "../firebase/config"
import firestore from '#react-native-firebase/firestore'
dbh.collection('PRD')
.where('GTIN', '==', data)
.get()
.then(documentSnapshot => {
console.log('MedData',documentSnapshot.data())
});
I am unsure how to filter the right medicament using the GTIN provided by the Barcode scanner and then save the specific field value for the description of this medicament to a variable.
Firebase is setup correctly since I am able to write whole collections and documents in it.
Here is the database structure, as you can see there is the PRD Collection with all the medicaments and every medicament containing the GTIN and DSCRD Fields:
The problem with your implementation is that you are trying to call documentSnapshot.data() after querying a collection. This is the syntax you would use if you were fetching a single document. Your current query will return a list of documents which you need to handle like this:
.then(querySnapshot => {
querySnapshot.forEach(doc => {
console.log('MedData', doc.data())
})
});
Assuming that the GTIN will fetch one unique document (will it?) then you can just use the only document returned by the query to get the name of the Medication like this:
var medName
dbh.collection('PRD')
.where('GTIN', '==', data)
.get()
.then(querySnapshot => {
querySnapshot.forEach(doc => {
console.log('MedData', doc.data())
medName = doc.data().DSCRD
})
});
I have this data
I do this query
firebase.database().ref(${path}/buy)
.orderByChild('price').limitToFirst(1)
.once('value')
.then(snapshot => console.log(snapshot.val()))
And I get this result
Then the question is
Is there an easy way to access the price attribute of the one object whose key I don't know?
e.g. snapshot.first().price or snapshot.only().price
Simply put, I want to avoid this
var result = snapshot.val()
var key = Object.keys(result)[0]
var price = result[key].price
When you execute a query against the Firebase Database, there will potentially be multiple results. So the snapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result.
In your callback you need to handle this list by using snapshot.forEach():
firebase.database().ref(${path}/buy)
.orderByChild('price').limitToFirst(1)
.once('value')
.then(snapshot => {
snapshot.forEach(function(child) {
console.log(child.val());
console.log(child.val().price);
})
})