I have this code here and I want to delete certain value inside the array "Answered". Is there a simple way to access the first value in the array? This is right but shows what I want to happen "Answered[0]" <- I want to get the first value in that array and delete it. Thank you in Advance
let uid = Auth.auth().currentUser?.uid
print(self.randomArray)
let wash = db.collection("users").document(uid!)
wash.updateData([
"Answered": FieldValue.arrayUnion([self.randomArray])
])
}
if(self.check.isEmpty != true){
self.whichQuestion = self.check[0]
self.whichQuestionString = String(self.whichQuestion)
db.collection("users").document(uid!).updateData([
"Answered": FieldValue.delete(),
]) { err in
if let err = err {
print("Error updating document: \(err)")
} else {
print("Document successfully updated")
}
}
If your array contains unique values however, you can remove the item with:
self.whichQuestionString = String(self.whichQuestion)
db.collection("users").document(uid!).updateData([
"regions": FieldValue.arrayRemove([whichQuestionString])
])
If you only know the index of the item, there is no way to remove it without knowing the entire array.
The recipe for this is:
Read the document from Firestore
Modify the array in your application code
Write the entire modified array back to Firestore
Also see (none of which unfortunately are for Swift):
Is there any way to update a specific index from the array in Firestore
Delete data from Firestore dynamically
Related
let reference = Firestore
.firestore()
.collection(FBKeys.CollectionPath.users)
.document(uid)
reference.getDocument { (document, error) in
if let document = document, document.exists {
let dataDescription = document?.data()
print("Document data: \(dataDescription)")
} else {
print("Document does not exist")
}
}
I have created a cloud database using firebase. I have collection name is "users" and I have email, favoriteArtsts, name, uid as the fields. What I want to do is I want to add more artists to the favoriteArtsts array. However, to do so, I have to first get the reference to the array. By following the firebase instructions, I was able to get the user_id. The code above is the code I have tried. The code shows all the fields. However, I don't know how to get the favoriteArtsts values only. Is there a way to get the favoriteArtsts values?
You can get a single field by doing document.get("favoriteAritsts") (notice your typo in favoriteAritsts in your screenshots.
You can also do document.data()["favoriteAritsts"]
Both of the above will give you a return type of Any? so you would need to do any optional cast of either one with as? [String]:
let array = document.get("favoriteAritsts") as? [String]
I am using Firestore. I am trying to listen for when a new user is added. The problem is, each user also has a friends dictionary. So when I use a snapshot, my code is detecting both events of (1) A new user being added and (2) a new friend being added.
I have tries iterating over the document changes data and restricting doc.document.data()["friends"] == nil. Why isn't this working/how can I properly add a restriction to only include when a new user is added?
func observeUsers(onSuccess: #escaping(UserCompletion)) {
Ref().firestoreUserRef.collection("users").addSnapshotListener { (querySnapshot, error) in
if error != nil {
print("error with observeUser snapshot")
return
}
querySnapshot?.documentChanges.forEach { doc in
//I want to detect that a new user was added, I do not want to detect if a friend was added
if (doc.type == .added) && doc.document.data()["friends"] == nil {
guard let dict = querySnapshot else { return }
for document in dict.documents {
var dictionary = [String : Any]()
dictionary = document.data()
if let user = User.transformUser(dict: dictionary) {
onSuccess(user)
}
}
}
}
}
}
The easiest way is starting from the data model to support the types of queries you want. In this case, when you create a new user (which I assume always has no friends), set the friends field explicitly to null. This will let you query for all new users:
Ref().firestoreUserRef.collection("users").whereField("friends", isEqualTo: NSNull()).addSnapshotListener ...
An assumption here is your transformUser process will update the document and replace null with either a list of friends of an empty array so that it no longer matches the query.
I have a view controller that lists data from a firestore database. Inside a firestore collection, I have a bunch of documents with the information shown in the list, and one document called order which contains one field which is an array of strings in the order I want them displayed. My code grabs this:
self.db.collection("officers").document(school).collection(grade).document("order").getDocument {(document, error) in
if let document = document, document.exists {
self.officerNames = (document.data()!["order"] as! Array<String>)
and then is supposed to use the strings in the array order (officerNames) to query the documents in that same collection (all the documents have a different role so it's only getting one document in the snapshot) and display them in the same order as the one set in order (officerNames).
for item in 1...self.officerNames.count {
self.db.collection("officers").document(school).collection(grade).whereField("role", isEqualTo: self.officerNames[item-1]).getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let officerMessage = document.data()["agenda"] as! String
let officerInfo = document.data()["short"] as! String
(a bunch of code here using that ^ ^ and due to the color I need item to be an integer)
}
}
}
}
I know that if I try printing item before the self.collection("officers")..... the numbers count by one but if I do that in the for document in querySnapshot..... they're all out of order meaning some documents are loaded faster than others. I have read about Async functions in Swift (although I do use those in JavaScript) but am really confused how to use them and hopefully, there is a simpler way to do this. Any way I can wait to make sure the previous document has been loaded and analyzed before iterating through the loop again?
Here's a screenshot of the database:
Honestly, you may want to examine your data structure and see if you can create one that doesn't require multiple queries like this. I can't quite tell what your data structure is, but if you update your question to include it, I can give some suggestions for how to refactor so you don't have to do 2 different get requests.
That being said, since Swift doesn't have promises like JS, it can be tough to keep data in order. For most cases, closures work well, as I wrote about in this blog. But they still won't preserve order in an array of async calls. Assuming you're using some array to store the officer's data, you can declare the size of the array up front by giving each one a default value. This would look something like this:
var officerArray = [Officer](repeating:Officer(), count: self.officerNames.count)
Of course, it'll be different depending on what kind of objects you're populating it with. I'm using some generic Officer object in this case.
Then, rather than appending the newly created Officer object (or whatever you're calling it) to the end of the array, add its value to its particular location in the array.
for item in 1...self.officerNames.count {
self.db.collection("officers").document(school).collection(grade).whereField("role", isEqualTo: self.officerNames[item-1]).getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let officerMessage = document.data()["agenda"] as! String
let officerInfo = document.data()["short"] as! String
// etc
officerArray[self.officerNames.count-1] = Officer(officerMessage: officerMessage, officerInfo: officerInfo) // or however you're instantiating your objects
}
}
}
}
This preserves the order.
I'm new to Swift/App development and am trying to learn how to work with a Firestore database. I am getting a response from Firestore and I'm able to print out the results. I don't know how to manipulate or use the data that I am receiving. I suspect it's something to do with the data type, I think Firestore provides the data back as a dictionary.
I want to be able to take the results from Firestore and but it into a if/switch statement and check if the input is true or false.
let db1 = Firestore.firestore()
db1.collection("firstDatabase").getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
print("\(document.documentID) => \(document.data())")
}
}
How would I go about this after receiving the data? Would I assign to a variable first then manipulate it in an If/Switch statement to check if the values are true or false?
I know I'm missing some basics but thank you in advance for helping a new coder!
Just create a dictionary with the data you are receiving from Firestore like this:
let dictionary = document.data() as [String : Any]
then check the dictionary values in you if or switch statements:
if dictionary["foo"] {
//Do something here
}
if values for the dictionary are not bool:
if dictionary["foo"] == "bar" {
//Do something here
}
I need to get all the users count from superuser and list those in a table view with there details.
Is there a code to directly get the count of documents inside a collection, other than using functions inside firebase console.
Or a Simple Query to traverse through the documents!
this will collect all the document for a collection and print them
db.collection("superUsers").getDocuments()
{
(querySnapshot, err) in
if let err = err
{
print("Error getting documents: \(err)");
}
else
{
var count = 0
for document in querySnapshot!.documents {
count += 1
print("\(document.documentID) => \(document.data())");
}
print("Count = \(count)");
}
}
You can count the documents in a snapshot:
snapshot.count
You can use
querySnapshot.documents.count
When you receive a SnapShot, it includes documents as you see in your FireStore Web Page. then you must get documents.count to get number of documents in that particular hierarchy you requested for.