I have a value that goes up by one every time a question is correctly answered (learn_streak) I am trying to check if this value is bigger than a value in core data (bsVoLearn, type: Int64)
the aim is to check whether or not the learn_streak is larger than bsVoLearn and if it is to set bsVoLearn to learn_streak
I have tried this in a function within content view
if learn_streak >= student.bsVoLearn { // error on this line
let student = Student(context: moc)
student.bsVoLearn = Int64(learn_streak)
try? moc.save()
}
however this didn't work (the error is that it can't find student in scope)
here is the solution I have found,
let student = Student(context: moc)
if learn_streak >= student.bsVoLearn {
student.bsVoLearn = Int64(learn_streak)
try? moc.save()
}
Related
I'm trying to retrieve a specific child of my Firebase database using swiftUI. To do that I use the simple expression
func addListeners() {
let database = Database.database(url: "https://someUrl")
let ref = database.reference(withPath: "users")
let currentUserId = "u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2"
let drivingTowardsRef = database.reference(withPath: "users/\(currentUserId)/drivingTowardsUsers")
print("Loading data from \(drivingTowardsRef)")
//THIS RIGHT HERE IS CAUSING THE PROBLEM
ref.observe(.childAdded) { snapshot in
print("Got TOP LEVEL data for user \(snapshot.key): \(String(describing: snapshot.value))")
}
//---------------------------------------
drivingTowardsRef.observe(.childAdded) { snapshot in
ref.child(snapshot.key).getData { (error, userSnapshot) in
if let error = error {
print(error)
} else {
print("Got arriving user data \(snapshot.key): \(String(describing: userSnapshot.value))")
}
}
}
}
The function will just return the entire database data
EDIT: The function returns the data from the first observer ref top level in this case users/ which in my case has two elements: niixi6iORjNn8gWq6tKvSi3Bxfc2, u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2
Got arriving user data niixi6iORjNn8gWq6tKvSi3Bxfc2: Optional({
niixi6iORjNn8gWq6tKvSi3Bxfc2 = {
aproxTime = 0;
distance = 0;
latitude = "37.33070704";
longitude = "-122.03039943";
parkingMode = searching;
userId = niixi6iORjNn8gWq6tKvSi3Bxfc2;
username = testeroNumero;
};
u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2 = {
aproxTime = 0;
distance = 0;
drivingTowardsUsers = {
niixi6iORjNn8gWq6tKvSi3Bxfc2 = {
approxTime = 0;
distance = "560.1447571016249";
};
};
latitude = "37.32984184";
longitude = "-122.02018095";
parkingMode = offering;
userId = u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2;
username = cleoBadu;
};
The key for the child path I pass him seems to be correct but it's still returning the entire top level collection instead of the single item...
EDIT: The problem seems to be on the first observer which messes up the .getData() of the ref.child(snapshot.key). Is that even possible?
Just commenting out that ref.observe(.childAdded) will automatically make the second ref.child(snapshot.key) behave totally normally
What am I missing?
I could get the entire database as a single mega dictionary and then get the child I want from there but it doesn't seem really conventional, especially when google's library offers the possibility to not do that.
EDIT: I added a printing statement that prints the url of the database ref. If I then type in the url on my browser, it redirects me on the FRT database and landing me on the correct object. So the url it's generating is correct and works perfectly fine.
Still the object returned by the getData() is the entire db
SN: I removed all codable structs as that is not the problem, so the question is more focused on the actual problem
EDIT: Created a simple view as that. On a clean project it works on my project it doesn't. I guess it's some sort of configuration but's it's hard to look into it.
PROBLEM: Whatever child(string) I pass him it returns the entire top level data either way (replacing so snapshot.key). For example: I pass the key "something" -> all users are returned, I pass the key "" all users are returned
I just tried to reproduce the problem with (mostly) your code and data, but am not getting the same behavior.
I put the equivalent data into a database of mine at: https://stackoverflow.firebaseio.com/68956236.json?print=pretty
And used this code in Xcode 1.2 with Firebase SDK version 8.6.1:
let ref: DatabaseReference = Database.database().reference().child("68956236")
let currentUserId: String = "u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2"
let drivingTowardsRef: DatabaseReference! = ref.child("\(currentUserId)/drivingTowardsUsers");
print("Loading data from \(drivingTowardsRef)")
drivingTowardsRef.observe(.childAdded) { snapshot in
ref.child(snapshot.key).getData { (error, userSnapshot) in
if let error = error {
print(error)
} else {
do {
//let parkingUser = try userSnapshot.data(as: ParkingUser.self)
print("Got data for user \(snapshot.key): \(String(describing: userSnapshot.value))")
} catch {
print("There has been an error while decoding the user location data with uid \(snapshot.key), the object to be decoded was \(userSnapshot). The decode failed with error: \(error)")
}
}
}
}
The output I get is:
Loading data from Optional(https://stackoverflow.firebaseio.com/68956236/u3Ebr6M3BAbP7PBSYYJ7q9kEe1l2/drivingTowardsUsers)
2021-08-27 10:39:09.578043-0700 Firebase10[36407:3458780] [] nw_protocol_get_quic_image_block_invoke dlopen libquic failed
Got data for user niixi6iORjNn8gWq6tKvSi3Bxfc2: Optional({
aproxTime = 0;
distance = 0;
latitude = "37.32798355";
longitude = "-122.01982712";
parkingMode = searching;
userId = niixi6iORjNn8gWq6tKvSi3Bxfc2;
username = testeroNumero;
})
As far as I can see this behavior is correct, but different from what you get. I hope knowing that I don't see the same behavior, and what versions I use, may be helpful to you.
This is not an issue with Firebase but rather client-side handling of the data returned, You’re expecting a Double within your Codable struct but supplying a String in the other end— Can you try:
public struct ParkingUser: Codable {
var latitude: String
var longitude: String
}
I'm trying to save back to CloudKit after updating a reference list and getting the error on the first line of this code block.
Error: Ambiguous reference to member 'save(_:completionHandler:)'
CKContainer.default().publicCloudDatabase.save(establishment) { [unowned self] record, error in
DispatchQueue.main.async {
if let error = error {
print("error handling to come")
} else {
print("success")
}
}
}
This sits within a function where the user going to follow a given location (Establishment). We're taking the existing establishment, and its record of followers, checking to see if the selected user is in it, and appending them to the list if not (or creating it if the list of followers is null).
Edit, in case helpful
//Both of these are passed in from the prior view controller
var establishment: Establishment?
var loggedInUserID: String?
#objc func addTapped() {
// in here, we want to take the logged in user's ID and append it to the list of people that want to follow this establishment
// which is a CK Record Reference
let userID = CKRecord.ID(recordName: loggedInUserID!)
var establishmentTemp: Establishment? = establishment
var followers: [CKRecord.Reference]? = establishmentTemp?.followers
let reference = CKRecord.Reference(recordID: userID, action: CKRecord_Reference_Action.none)
if followers != nil {
if !followers!.contains(reference) {
establishmentTemp?.followers?.append(reference)
}
} else {
followers = [reference]
establishmentTemp?.followers = followers
establishment = establishmentTemp
}
[this is where the CKContainer.default.....save block pasted at the top of the question comes in]
I've looked through the various posts on 'ambiguous reference' but haven't been able to figure out the source of my issue. tried to explicitly set the types for establisthmentTemp and followers in case that was the issue (based on the solutions to other related posts) but no luck.
Afraid I'm out of ideas as a relatively inexperienced newbie!
Help appreciated.
Documenting the solution that I figured out:
Combination of two issues:
I was trying to save an updated version of a CK Record instead of updating
I was not passing a CK Record to the save() call - but a custom object
(I believe point two was the cause of the 'ambiguous reference to member'
error)
I solved it by replacing the save attempt (first block of code in the question) with:
//first get the record ID for the current establishment that is to be updated
let establishmentRecordID = establishment?.id
//then fetch the item from CK
CKContainer.default().publicCloudDatabase.fetch(withRecordID: establishmentRecordID!) { updatedRecord, error in
if let error = error {
print("error handling to come")
} else {
//then update the 'people' array with the revised one
updatedRecord!.setObject(followers as __CKRecordObjCValue?, forKey: "people")
//then save it
CKContainer.default().publicCloudDatabase.save(updatedRecord!) { savedRecord, error in
}
}
}
As I try to update an existing entry in my Core Data DB, I fetch the desired item by id, change it to a new item and save in context.
However, when I fetch the object and replace it, I get the warning "Core Data Object was written to, but never read." It does make sense since I'm not really using that object, but as I understand it, just giving it a value saves it in Core Data.
static var current: User? {
didSet {
if var userInCoreData = User.get(with: current?.id), let current = current { //userInCoreData is the value with the warning
userInCoreData = current
}
CoreDataManager.saveInContext()
}
}
static func get(with id: String?) -> User? {
guard let id = id else { return nil }
let request: NSFetchRequest = User.fetchRequest()
let predicate = NSPredicate(format: "id = %#", id)
request.predicate = predicate
do {
let users = try CoreDataManager.managedContext.fetch(request)
return users.first
} catch let error {
print(error.localizedDescription)
return nil
}
}
I want to make sure, is this the recommended process to overwrite a value in Core Data, or am I doing something wrong?
This section
if var userInCoreData = User.get(with: current?.id), let current = current { //userInCoreData is the value with the warning
userInCoreData = current
}
seems just updating local variable userInCoreData, not User object in Core Data.
So the warning says "you fetched data from core data and set to a variable, but you set another value to the variable soon, never use the first value from core data. Is it OK?"
What you really want to do is something like this?
if var userInCoreData = User.get(with: current?.id), let current = current {
userInCoreData.someValue = current.someValue
userInCoreData.anotherValue = current.anotherValue
}
I have close to 7K items stored in a relation called Verse. I have another relation called Translation that needs to load 7K related items with a single call from a JSON file.
Here is my code:
let container = getContainer()
container.performBackgroundTask() { (context) in
autoreleasepool {
for row in translations{
let t = Translation(context: context)
t.text = (row["text"]! as? String)!
t.lang = (row["lang"]! as? String)!
t.contentType = "Verse"
t.verse = VerseDao.findById(row["verse_id"] as! Int16, context: context)
// this needs to make a call to the database to retrieve the approparite Verse instance.
}
}
do {
try context.save()
} catch {
fatalError("Failure to save context: \(error)")
}
context.reset()
}
Code for the findById method.
static func findById(_ id: Int16, context: NSManagedObjectContext) -> Verse{
let fetchRequest: NSFetchRequest<Verse>
fetchRequest = Verse.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "verseId == %#", id)
fetchRequest.includesPropertyValues = false
fetchRequest.fetchLimit = 1
do {
let results =
try context.fetch(fetchRequest)
return results[0]
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
return Verse()
}
}
This works fine until I add the VerseDao.findById, which makes the whole process really slow because it has to make a request for each object to the Coredata database.
I did everything I could by limiting the number of fetched properties and using NSFetchedResultsController for data fetching but no luck.
I wonder if there's any way to insert child records in a more efficient way? Thanks.
Assuming your store type is persistent store type is sqlite (NSSQLiteStoreType):
The first thing you should check is whether you have an Core Data fetch index on the Verse objects verseId property. See this stack overflow answer for some introductory links on fetch indexes.
Without that, the fetch in your VerseDao.findById function may be scanning the whole database table every time.
To see if your index is working properly you may inspect the SQL queries generated by adding -com.apple.CoreData.SQLDebug 1 to the launch arguments in your Xcode scheme.
Other improvements:
Use NSManagedObjectContext.fetch or NSFetchRequest.execute (equivalent) instead of NSFetchedResultsController. The NSFetchedResultsController is typically used to bind results to a UI. In this case using it just adds overhead.
Don't set fetchRequest.propertiesToFetch, instead set fetchRequest.includesPropertyValues = false. This will avoid fetching the Verse object property values which you don't need to establish the relation to the Translation object.
Don't specify a sortDescriptor on the fetch request, this just complicates the query
I am running into some trouble importing a large .csv file in OS X using Core Data on a background thread.
My simplified data model is a Dataset which has a to-many relationship to many Entries. Each entry is a line in the .csv file (which has a bunch of attributes that I'll leave out for brevity). Following what I have read about efficiently importing lots of data, along with how to make a progress indicator work properly, I have created a managed object context for the purposes of going the import.
I am having trouble with two things:
I need to hang on to a reference to the new Dataset at the end of the import, because I need to select it in the popup. this will be done in the main thread, but for efficiency (and to make my NSProgressIndicator work) the new dataset is created on the background thread, with the background MOC.
From what I read, batching the import, so that the background MOC saves and resets, is the best way to stop the import from eating up too much memory. That does not turn out to be the case so far - it looks like gigs of memory is being used even for files in the tens of megabytes. Also, once I reset my import MOC, it cannot find the data for the inDataset, and so cannot create the relationship between all subsequent Entries and the Dataset.
I've posted the simplified code below. I have tried refreshObject:mergeChanges, without good results. Can anyone point me at what I am doing wrong?
let inFile = op.URL
dispatch_async(dispatch_get_global_queue(priority, 0)) {
//create moc
let inMOC = NSManagedObjectContext()
inMOC.undoManager = nil
inMOC.persistentStoreCoordinator = self.moc.persistentStoreCoordinator
var inDataset : inDataset = Dataset(entity: NSEntityDescription.entityForName("Dataset", inManagedObjectContext: inMOC)!, insertIntoManagedObjectContext: inMOC)
//set up NSProgressIndicator here, removed for clarity
let datasetID = inDataset.objectID
mocDataset = self.moc.objectWithID(datasetID) as! Dataset
let fileContents : String = (try! NSString(contentsOfFile: inFile!.path!, encoding: NSUTF8StringEncoding)) as String
let fileLines : [String] = fileContents.componentsSeparatedByString("\n")
var batchCount : Int = 0
for thisLine : String in fileLines {
let newEntry : Entry = Entry(entity: NSEntityDescription.entityForName("Entry", inManagedObjectContext: inMOC)!, insertIntoManagedObjectContext: inMOC)
//Read in attributes of this entry from this line, removed here for brevity
newEntry.setValue("Entry", forKey: "type")
newEntry.setValue(inDataset, forKey: "dataset")
inDataset.addEntryObject(newEntry)
dispatch_async(dispatch_get_main_queue()) {
self.progInd.incrementBy(1)
}
batchCount++
if(batchCount > 1000){
do {
try inMOC.save()
} catch let error as NSError {
print(error)
} catch {
fatalError()
}
batchCount = 0
inMOC.reset()
inDataset = inMOC.objectWithID(datasetID) as! Dataset
// fails here, does not seem to be able to find the data associated with inDataset
}
}// end of loop for reading lines
//save whatever remains after last batch save
do {
try inMOC.save()
} catch let error as NSError {
print(error)
} catch {
fatalError()
}
inMOC.reset()
dispatch_async(dispatch_get_main_queue()) {
//This is done on main queue after background queue has read all line
// I thought the statement just below would refresh mocDataset, but no luck
self.moc.refreshObject(mocDataset, mergeChanges: true)
//new dataset selected from popup
let datafetch = NSFetchRequest(entityName: "Dataset")
let datasets : [Dataset] = try! self.moc.executeFetchRequest(datafetch) as! [Dataset]
self.datasetController.addObjects(datasets)
let mocDataset = self.moc.objectWithID(datasetID) as! Dataset
//fails here too, mocDataset object has data as a fault
let nDarray : [Dataset] = [mocDataset]
self.datasetController.setSelectedObjects(nDarray)
}
}