How can I get the document id of a collection present in the cloud Firestore?
I tried to get it by using the
firebase.firestore().collection("collectionName").doc().id
but I didn't get the appropriate result.
firebase.firestore().collection("societies").doc().id and it returns a id which is not equivalent to society documentId
That's correct because everytime when you are using the above line of code, you are generating a new document id which will never be the same with one that already exist in your database.
In order to use a new document id, first you need to generate it (as you already do) and then store it in a variable. Having that varaible which holds that id, you can use it to get that particular document from the database by passing this id as an argument to the doc(id) function:
firebase.firestore().collection("societies").doc(this.myId)
Related
Is it possible to update Firestore map's keys? I'm trying to do so through the Firestore dashboard and the key field is disabled as can be seen in the screenshot below? Does that mean that instead of updating the key, one needs to first delete the old entry and then create a new one?
There is no way to change the name of a field in Firestore. The API doesn't have such an operation, and (for that reason) it also isn't in the Firebase console.
You'll have to add a new field with the same value, and delete the old field.
Due to a weird situation where my Flutter app crashes if a query for authenticated user returns null, I'd like to do a short-term workaround by creating a transaction automatically whenever a user is created in the user collection.
This should reference a record in the Transactions collection by the Document Reference.
However, I can't seem to create a custom function which simply returns that value: /ads/WgtrMUIwjmVeyjQ6UwMl
I'm working on something like this:
I want to pass it through a Function as return value.
Thanks.
Hello, I have a problem I created a Registration form and im trying to check if there is any user which have a certain username inside the Firebase Db. I tried to get the reference of all the users.
var users = Database.database().reference("users")
But I don't know how I could check if there is any user with a specified username.
You'll want to use a query for that. Something like:
let query = users.queryOrdered(byChild: "username").equalTo("two")
Then execute the query and check whether the result snapshot exists.
Note though that you won't be able to guarantee uniqueness in this way. If multiple users perform the check at the same time, they may both end up claiming the same user name.
To guarantee a unique user name, you will need to store the user names as the key - as keys are by definition unique within their parent node. For more on this, see some of these top search results and possibly also from here.
I'm trying to set up a webpage that communicates with a Moodle page. I need different data from a database activity and want to create new entries. Note that I am not talking about the SQL database in BG, it is the activity database in courses.
The information should be retrieved/transferred via the REST API, an HTML POST Request. My problem is that I don't know how to add a new record to the database activity because I cannot transfer the data array. Only the first parameter given appears in my database.
E.g. i tried ...&wsfunction=mod_data_add_entry&databaseid=10&data[0][fieldid]=66&data[0][value]=12&data[1][fieldid]=67&data[1][value]=test
And many other combinations. Always only the first parameter is shown in the database.
The docs tell me this (Pseudocode):
//The fields data to be created
list of (
object {
fieldid int //The field id.
subfield string Default to "" //The subfield name (if required).
value string //The contents for the field always JSON encoded.
}
)
Alternatively:
REST (POST parameters)
data[0][fieldid]= int
data[0][subfield]= string
data[0][value]= string
I cannot find anywhere else something called a "subfield".
Any ideas?
Okay, found it. You have to put your values in "", unless they are not a number. Seems like there is a connection with this special activity because you don't have to do it elsewhere.
Recently i migrated all my parse data to MongoLab. i'm saving documents (parse object) directly to mongoDb using MongoClient.save(...), and not using parse SDK.
now mongo generate auto id, in my case - '56eac5ea1ac8242012ae4ed9', and parse dashboard not show any row in this class till i delete this object (document) and i'm getting the next error: objectId must be a string: ObjectIdHex("56eac5ea1ac8242012ae4ed9")
should i save id differently?
how to convert my id to regular Parse object id? (if i reallty need it?)
any solution?
I know parse dashboard is temporary, but right now it helps
It occurs because by default Mongo create an ObjectId for each object stored in its collections. To overcome it, you have to order Mongo store your own generated Id.
You can do it by sending the _id property in your object that is being stored in Mongo. Something like this:
db.collection('_User').save({_id: yourid, ...})
You can generate any random string id, but it would be good to generate the _id as the same way Parse Server does. If you check Parse Server repository (https://github.com/ParsePlatform/parse-server/blob/master/src/cryptoUtils.js) you can find how the id is generated.
Anyway. There are solutions, like www.back4app.com, that already provides full hosting of both parse server, parse dashboard and database
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Disclosure: I am founder of back4app.com