In my app I create a default array of data upon user registration and add it under that user id in the following manner (using a service):
function addDefaultData(){
var defCategories = ['','data1',
'data2',
'data3',
'data4'];
var updates = {};
updates['/user-data/' + firebase.auth().currentUser.uid + '/' + 'categories'] = defCategories;
return firebase.database().ref().update(updates);
}
}
After registration the user can change this array, add or remove single item at a time. I read here but that does not help me. This is how the data looks in firebase db:
-appName-fomefirebaseid123
-user-data
-userID123687FHGJH4546HGJ
+5_2017
-categories
0: ""
1: "data1"
2: "data2"
3: "data3"
4: "data4"
How can I manipulate this array? Remove or add new items to it?
The Firebase team believes that "Arrays are Evil" (see: https://firebase.googleblog.com/2014/04/best-practices-arrays-in-firebase.html).
In that same article, they state: "Firebase has no native support for arrays. If you store an array, it really gets stored as an 'object' with integers as the key names."
I'd read the above blog and adjust my expectations and approach to interacting with Firebase accordingly.
In your case, if you want to delete index "0" of categories, you're really deleting key "0" of the categories document.
Related
To optimize usage, I have a Firestore collection with only one document, consisting in a single field, which is an array of strings.
This is what the data looks like in the collection. Just one document with one field, which is an array:
On the client side, the app is simply retrieving the entire status document, picking one at random, and then sending the entire array back minus the one it picked
var all = await metaRef.doc("status").get();
List tokens=all['all'];
var r=new Random();
int numar=r.nextInt(tokens.length);
var ales=tokens[numar];
tokens.removeAt(numar);
metaRef.doc("status").set({"all":tokens});
Then it tries to do some stuff with the string, which may fail or succeed. If it succeeds, then no more writing to the database, but if it fails it fetches that array again, adds the string back and pushes it:
var all = await metaRef.doc("status").get();
List tokens=all['all'];
List<String> toate=(tokens.map((element) => element as String).toList());
toate.add(ales.toString());
metaRef.doc("status").set({"all":toate});
You can use the methods associated with the Set object.
Here is an example to check that only 1 item was removed:
allow update: if checkremoveonlyoneitem()
function checkremoveonlyoneitem() {
let set = resource.data.array.toSet();
let setafter = request.resource.data.array.toSet();
return set.size() == setafter.size() + 1
&& set.intersection(setafter).size() == 1;
}
Then you can check that only one item was added. And you should also add additional checks in case the array does not exist on your doc.
If you are not sure about how the app performs the task i.e., successfully or not, then I guess it is nice idea to implement this logic in the client code. You can just make a simple conditional block which deletes the field from the document if the operation succeeds, either due to offline condition or any other issue. You can find the following sample from the following document regarding how to do it. Like this, with just one write you can delete the field which the user picks without updating the whole document.
city_ref = db.collection(u'cities').document(u'BJ')
city_ref.update({
u'capital': firestore.DELETE_FIELD
})snippets.py
I am working with Google Sheets, and I am trying to send data to my Firestore database. I have been able to write to Firestore from Google Sheets, but I can't seem to update a field without completely messing things up.
This is my current testing code:
function getFireStore() {
const email = "your#email.gserviceaccount.com"
const key = "-----BEGIN PRIVATE KEY-----\n your key here \n-----END PRIVATE KEY-----\n";
const id = "project_id";
var firestore = FirestoreApp.getFirestore(email, key, id);
var spreadsheet = SpreadsheetApp.getActive()
var sheet = spreadsheet.getActiveSheet()
var data = {
numIndividuals: sheet.getRange(23, individuals).getValue(),
numTeams: sheet.getRange(23, teams).getValue(),
schoolID: sheet.getRange(23, schoolID).getValue(),
uid: sheet.getRange(23, uid).getValue(),
};
firestore.createDocument("competitions/" + sheet.getRange(23, compId).getValue() + "/registration/abcdefg", data)
}
I understand after playing around with this that it will create a new subcollection titled "registration" with the document "abcdefg." The same thing happens when I use the updateDocument function, as well.
For the website that is reading and writing to this particular Firestore database, I use a similar function .update() to update the document with the correct information. However, in Google Sheets, while it would work the same way it is much more convoluted and tedious to do so.
The way that I came up with for trying to update the document was basically copying everything and adding in the new data.
However, this is seriously tedious and messy. Just copying the data that isn't changed looks like this:
var data = {
compDate: competitions.fields.compDate.stringValue,
contact: competitions.fields.contact.stringValue,
email: competitions.fields.email.stringValue,
grade: competitions.fields.grade.stringValue,
id: competitions.fields.id.integerValue,
maxTeams: competitions.fields.maxTeams.integerValue,
regDate: competitions.fields.regDate.stringValue,
schTeams: competitions.fields.schTeams.integerValue,
schedule: competitions.fields.schedule.stringValue,
site: competitions.fields.site.stringValue,
status: competitions.fields.status.stringValue,
timestamp: competitions.fields.timestamp.integerValue,
user: competitions.fields.user.stringValue,
year: competitions.fields.year.stringValue,
}
The data I want to change is a .mapValue with multiple fields where one of the fields can have multiple fields, which also have multiple fields.
Here's the hierarchy for the field I need to update:
first registration and first team
I know I could do multiple for-loops and whatnot on this, but my question is: is there a simpler way to do this, or do I have to go through and loop over everything to extract only what I want?
As a sidenote, what gets sent to Firestore if I put in the data I got from Firestore using the spread operator, without any editing, it includes every child from the above image. As in, I would have registration -> mapValue -> fields -> 0 -> mapValue -> fields -> etc. And, I don't want those mapValue and fields included, just that actual data (i.e. registration -> 0 -> {schoolID, uid, names, etc.}).
I want to save users data in firebase , should I save theme as map in database like this:
[
{
"id":1
"name":"ab"
"age" : 34
}
{
"id":2
"name":"aab"
"age" : 4
}
{
"id":3
"name":"aeb"
"age" : 25
}
]
or there better idea to do that?
I would suggest use FireStore for such data.
These types of incremental approaches aren't possible in firebase firestore. Alternatively, you can use a firebase function to add id while creating a new user. When a new document has been created the function will call the previous user-id as an integer and increment the id number by 1 and post it as the next user-id. But if you want to have the feature to delete the user document in the future then the id will be also removed as usual.
I would like to create into Firebase an "AccountQueues" object that will have account and names or the word "FREE" if it doesn't have account.
AccountQueues
-LEf-OrdKi65WG0NkQSG
AccountID:
"GR215"
Name:
"FREE"
When a user register I would like to take the first FREE AccountID and update it with the name of the user. Thank you for your help. I am developing an ionic 3 mobile app with this functionality.
You could use a query to check for an account that is free and limit it to the first search result. You want to use snapshotChanges() in order to return the key of the object.
returnedKey = null;
this.fireDB.list('AccountQueues', ref => ref.orderByChild('Name').equalTo('FREE').limitToFirst(1)).snapshotChanges().take(1).subscribe(res => {
res.map(doc => {
this.returnedKey = doc.key; //use this key to update object
});
});
Using the returned key from the query you can then update that object
this.fireDB.object(`AccountQueues/${this.returnedKey}`).update({Name:'Bob'});
I am trying to access to a object into another object in my firebase database, i have a structure like this:
I want to get all the objects that have the email that i send by parameters, i am using .child to access to the childs into my object but i am not success with the query, this is my code
$ ref_db.child("/groups").child("members").orderByChild("email").equalTo(email).once("value", (snapshot)=>{
console.log(snapshot.val());
});
The snapshot.val() always is undefined.
could you help me with the query?
One efficient way to get "all the groups that have that email inside the members object" would be to denormalize you data and have another "main node" in your database where you store all "members" (i.e. their email) and the "groups" they belong to.
This means that each time you add a "member" node under a "group" (including its email) you will also add the group as a child of the member email, in this other "main node".
More concretely, here is how would be the database structure:
Your current structure:
- groups
- -LB9o....
...
- members
- -LB9qbd....
-email: xxxx#zzz.com
- -LBA7R....
-email: yyyyy#aaaa.com
And the extra structure:
- groupsByMembers
- xxxxxx#zzzcom
- Grupo1: true
- yyyyy#aaaacom
- Grupo1: true
- Grupo2: true
- bbbcccc#dddcom
- Grupo6: true
- Grupo8: true
Note that in the "extra structure" the dots within an email address are removed, since you cannot include a point in a node id. You will have to remove them accordingly when writing and querying.
This way you can easily query for the list of groups a member is belonging to, as shown below. Without the need to loop several times over several items. This dernomalization technique is quite classic in NoSQL databases.
const mailToSearchFor = xxxx.xx#zzz.com;
const ref = database.ref('/groupsByMembers/' + mailToSearchFor.replace(/\./g, ''));
ref.once('value', snapshot => {
const val = snapshot.val();
for (let key in val) {
if (val.hasOwnProperty(key)) {
console.log(key);
}
}
});
In order to write to the two database nodes simultaneously, use the update method as explained here https://firebase.google.com/docs/database/web/read-and-write#update_specific_fields
This is because you have a random key before members, you need to go through the path and not skip a node, to be able to access the values:
ref_db.child("groups").child("-LB9oWcnE0wXx8PbH4D").child("members").orderByChild("email").equalTo(email).once("value", (snapshot)=>{
console.log(snapshot.val());
});