So I'm working on a personal project to learn react-native and Firestore.
I have a DB like this:
And I want my code to add a new battery in the array batteries.
The elements in the array are just a map{string, string}
The problem is that when I update the array with a new brand that's work but if I want to update it with the same brand again have,
so having by the end
batteries[0]: {'brand': 'cestmoi'}
batteries[1]: {'brand': 'cestmoi'}
The DB doesn't update, doesn't have any error or so.
I don't understand why and I followed their tutorial. Here is my code:
async function addData(collection, doc, value) {
console.log(`Add data ${value.brand}`)
try {
const result = await firestore()
.collection(collection)
.doc(doc)
.set({
batteries: firestore.FieldValue.arrayUnion(value)
})
console.log(result);
return result;
} catch (error) {
return error;
}
}
I use try-catch by habit but I don't know if the then...catch is better or not.
As already #windowsill mentioned in his answer, there is no way you can add duplicate elements in an array using client-side code. If your application requires that, then you have to read the entire array, add the duplicates and then write the document back to Firestore.
However, if you want to update an existing element in an array of objects (maps) then you have to use arrayUnion with the entire object. If you want to understand the mechanism better, you can read the following article which is called:
How to update an array of objects in Firestore?
arrayUnion says that it "adds elements to an array but only elements not already present". Maybe it does a stringify or something to check equality and therefore doesn't add the new element. I think you'll have to 1. get the current list, 2. add your element, 3. set the batteries field to the updated list.
Related
I have the following test data
1: {
match: "Game 1",
scorer: ["foo","bar"] //this could also be an object
}
My question is how do I correctly append new value to an array without overwriting it? My idea was to retrieve existing data then spread it like so [...currentData, "bob"]. Is there a better alternative?
const addScorer = (matchId) => {
return update(ref(db, path), {
scorer: ["bob"]
})
}
There is no atomic operation to add an item to an array directly in the database. This means you'll need to:
Read the array into your application code
Append the item to the array
Write the entire array back to the database
This is one of the many reasons why Firebase recommends against using arrays for lists of data, but instead has a push() operation that circumvents most problems. For more on this, see the link to the document that Nilesh included in their comment, or read this article on Best Practices: Arrays in Firebase.
I would like to update the completed property of an object in an array in Firestore, but I have no idea how to reach that specific element in the array. The image will show the structure.
I have come up this far but don't know how to choose, for example, item 1 in the array. I was thinking of using its ID (it has an id property) but don't know how to get there.
const businessRef = db.collection('approvedBusinesses').doc(businessId)
try {
businessRef.update({
[`bookings.${currentDate} ????? `]: true // what to add after currentDate?
})
By the way, this is how the array was created (and how other objects are pushed to it)
const bookingObj = {
carro: 'PASSA_CARRO',
completed: false,
userId: userObject.uid,
}
businessRef.update({
[`bookings.${currentDate}`]: firebase.firestore.FieldValue.arrayUnion(bookingObj),
})
Firestore does not have an operation that allows you to update an existing item in an array by its index.
To update an existing item in the array, you will need to:
Read the entire document into your application.
Modify the item in the array in your application code.
Write back the entire array to the document.
I'm pretty sure this has been asked before, so let me see if there's an answer with an example.
Also see:
How to remove an array element according to an especific key number?
Simple task list ordering - how to save it to Firebase Firestore?
How to update only a single value in an array
How to update an "array of objects" with Firestore?
I have a firestore firebase database , in which I have a collection users
there is an array in the collection and in the array there is a map
in map there is a field qty.. I want to increment that qty value..
using increment doesnt help as the qty is inside a array index
db.collection("users").doc(checkId).update({
myCart: firebase.firestore.FieldValue.arrayUnion({
qty: firebase.firestore.FieldValue.increment(1),
}),
this is the error Output =>
Uncaught (in promise) FirebaseError: Function FieldValue.arrayUnion() called with invalid data. FieldValue.increment() can only be used with update() and set()
My answer below won't work, given that the qty is in an array. The only way to update an item in an array is to read the entire document, update the item in the array, and then write the entire array with the updated item back to the document.
An alternative would be to use a map instead of an array, and then update the qty using the approach outlined in my (old, and non-working) answer below 👇
You need to specify the full path to the field you're trying to update. So I think in your case, that'll be:
db.collection("users").doc(checkId).update({
"myCart.0.qty": firebase.firestore.FieldValue.increment(1)
}),
The field you want to update is embedded in an array. In this case, you can't use FieldValue.increment(), since it's not possible to call out an array element as a named field value.
What you'll have to do instead is read the entire document, modify the field in memory to contain what you want, and update the field back into the document. Also consider using a transaction for this if you need to update to be atomic.
(If the field wasn't part of an array, you could use FieldValue.increment().)
As of today (29-04-2020)... this is tested by me.
Suppose my data structure is like this:
collection: Users
Any document: say jdfhjksdhfw
It has a map like below
map name: UserPageVisits
map fields: field1,field2,field3 etc
Now we can increment the number field in the map like below:
mapname.field1 etc...
That is use the dot operator to access the fields inside the map just like you would do to an object of javascript.
JAVA Code (Android), update the field using transactions so they can complete atomically.
transaction.update(<documentreference object>,"UserPageVisits.field1",FieldValue.increment(1));
I have just pushed a version of my app which uses this concept and it's working.
Kudos !!
My Best Regards
Previous answers helped me as well, but dont forget about the "merge" property!!! Otherwise it will overwrite your entire array, losing other fields.
var myIndex = 0;
const userRef = db.collection('users').doc(checkId);
return userRef.update({
'myCart.${myIndex}.qty': admin.firestore.FieldValue.increment(1)
}, {
merge: true
});
I'm using Firebase and Vuejs to create an database element, which has object array inside.
That's how the field looks, and I want to add tasks through the form into the 'moreTasks' as an array.
I tried using this, but it just creates new entity in the database.
db.collection('Tasks').add({
tasker: this.tasker.taskerName
})
I also tried checking API but I couldnt understand the refs, because I was using different methods to achieve that goal.
creatTask() {
db.collection('Tasks').add({
task_id: this.task_id,
name: this.name,
What would be correct way to approach this problem?
You can append an item to an array using FieldValue.arrayUnion() as described in the documentation. For example:
// Atomically add a new region to the "regions" array field.
washingtonRef.update({
regions: firebase.firestore.FieldValue.arrayUnion("greater_virginia")
});
The accepted answer used to be correct but is now wrong. Now there is an atomic append operation using the arrayUnion method:
https://firebase.google.com/docs/firestore/manage-data/add-data#update_elements_in_an_array
This is true as long as you are using firestore and not real time db (which I assume is the case from the tags)
There are plenty of $addToSet topics out there, but after an hour of searching I still don't know how to evaluate in meteor-serverside-javascript-code if $addToSet added a new element to an array or it was a duplicate match.
The closest one I found was How to check if Mongo's $addToSet was a duplicate or not, but I don't know how to get a db object within meteor.
As written in other posts, the callback-function as a last parameter of the update method always returns 1 and it's always successful, no matter it's a duplicate or distinct element.
If there is no solution currently, I would like to know if there are other ways of checking a nested array (inside one specific collection) for a specific element. A simple true/false result information would be enough.
EDIT:
Ok, I managed to get the Bulk Update working now with the following lines:
var db = MongoInternals.defaultRemoteCollectionDriver().mongo.db;
var col = db.collection("posts");
var batch = col.initializeOrderedBulkOp();
batch.find({_id: postid}).upsert().updateOne({"$addToSet": ...});
batch.execute(function(err, result) {
if (err) throw err;
console.log("RESULT: ", JSON.stringify(result));
//db.close();
});</code>
The $addToSet works with this implementation, but the result object returned from the execution, still, is always the same:
RESULT: {
"ok":1,
"writeErrors":[],
"writeConcernErrors":[],
"nInserted":0,
"nUpserted":0,
"nMatched":1,
"nModified":null,
"nRemoved":0,
"upserted":[]
}
The interesting value nModified stays null both for an update and (duplicate found) skip.
Any ideas?
If I re-phrase the question, you're trying to figure if what you're about to insert is already there.
Why not simply query the object for it before attempting to insert?
If you have a set (array) you can simply do
db.collection.find({array_key: object_to_find_in_array})
and see if it returns an object or nothing. Then update as necessary.