Process to change data model - swift

How to change the .xcdatamodeld file i.e. the data model?
Since the program has already been run and the Persistent Store Coordinator (PSC) contains a url to .sqlite, .sqlite-shm and .sqlite-wal files on disk I think the process is as follows but am unsure. Any input would be appreciated.
Run code below to delete the url from PSC.
Delete sqlite files from disk.
Change .xcdatamodeld file.
CodeGen is set to manual so create new managed object subclasses.
Make appropriate changes to code.
Run program which I assume will enter a url into the PSC and create the 3 sqlite files on disk but now based on the new .xcdatamodeld file.
func deletePersistentStore() {
guard let persistentStoreURL = container.persistentStoreCoordinator.persistentStores.first?.url
else {
print("URL Missing")
return
}
do {
try container.persistentStoreCoordinator.destroyPersistentStore(
at: persistentStoreURL,
ofType: "SQLite",
options: nil)
} catch {
print("Persistent Store Not Deleted: \(error) - \(error.localizedDescription)")
}
print("\(container.persistentStoreCoordinator.persistentStores.count)")
// prints 0
print("\(String(describing: container.persistentStoreCoordinator.persistentStores.first?.url) )")
// prints nil
}

It sounds like you’re still developing this app and that it’s not released yet. If that’s true, you could do something like this. But it would be easier to delete the app from your phone (or simulator), change the model, and then install a new copy of the app.
That would let you skip steps 1 and 2.
If your app is already released, you should look into Core Data model migration. It’s a process that lets you update the data model without deleting existing data. In most cases it’s nearly automatic, but it depends on how much your model is changing.

Related

Ffmpeg for use in iOS application coded in Swift

I have been browsing the web, even this website... bu cannot find a good option to implement ffmpeg functionality in an iOS application made in swift.
Options looked at and reasons why they are not solutions:
SwiftFFmpeg - I am not sure it can run on iOS, plus I don't see an option to run my desired Ffmpeg command.
MobileFFmpeg - Not maintained anymore, and a new project by the same founders created a "better altenrative" called ffmpeg-kit.
ffmpeg-kit - looks amazing, but their API only allows for interaction in the Objective-C language.
Any solutions anyone can give me?
First...
Make sure you understand what "packages" are available. You can build it yourself, but to be honest, unless you have a very specific reason, I'd just use the pre-build packages. See "8. Packages" of the ffmpeg-kit README.MD to see what's on offer
Second
Go to the Releases and find the version you're interested (I used FFmpegKit Native v4.5.1), scroll down and expand the "Assets" list for the release you're interested in.
For this experiment I used ffmpeg-kit-full-4.5.1-macos-xcframework.zip. If you're doing this in iOS, the workflow is basically the same, you just need to take into account that your file access is sandboxed (and yes, I've done this, and yes, it takes a long time to transcode video, compared to a desktop)
Third
Create a new Xcode project. Again, for this experiment, I created a "MacOS App" using "Storyboards" as the UI (you could try using SwiftUI, but that's another layer of complexity this example didn't need right now)
Unzip the *xcframework.zip file you download from the last step.
In Xcode, select the "project" node, select the MacOS target (🤞 there's only one target).
Select "General", drag the *.xcframework folders from Finder to the "Frameworks, Libraries and Embedded Content" section of your project
Forth
For this experiment, I opened the ViewController class (which was automatically created by Xcode) and simply added...
func syncCommand() {
guard let session = FFmpegKit.execute("-i file1.mp4 -c:v file2.mp4") else {
print("!! Failed to create session")
return
}
let returnCode = session.getReturnCode()
if ReturnCode.isSuccess(returnCode) {
} else if ReturnCode.isCancel(returnCode) {
} else {
print("Command failed with state \(FFmpegKitConfig.sessionState(toString: session.getState()) ?? "Unknown") and rc \(returnCode?.description ?? "Unknown").\(session.getFailStackTrace() ?? "Unknown")")
}
}
func asyncCommand() {
FFmpegKit.executeAsync("-i file1.mp4 -c:v file2.mp4") { session in
guard let session = session else {
print("!! Invalid session")
return
}
guard let returnCode = session.getReturnCode() else {
print("!! Invalid return code")
return
}
print("FFmpeg process exited with state \(FFmpegKitConfig.sessionState(toString: session.getState()) ?? "Unknown") and rc \(returnCode).\(session.getFailStackTrace() ?? "Unknown")")
} withLogCallback: { logs in
guard let logs = logs else { return }
// CALLED WHEN SESSION PRINTS LOGS
} withStatisticsCallback: { stats in
guard let stats = stats else { return }
// CALLED WHEN SESSION GENERATES STATISTICS
}
}
The code above is basically the "2. Execute synchronous FFmpeg commands." and "4. Execute asynchronous FFmpeg commands by providing session specific execute/log/session callbacks." examples from the ffmpeg-kit/apple documentation
!! Important !! - don't forget to add import ffmpegkit to the start of the file!
At this point, this should now compile (you'll get a couple of warnings about logs and stats not been used, you can ignore those).
After thoughts...
You should realise by now that the code I've provided won't actually run, for two reasons.
I've not actually called either func from anywhere (I tested it by placing it in the viewDidLoad func of the ViewController class)
The input file, used in the execute command, doesn't exist. You will need to provide an actual reference to an actual file, preferably with an absolute path. This, how ever, may require you to change the "App Sandbox" settings under the targets "Signing and Capabilities"
Xcodes auto code suggestions aren't bad and I mostly filled out the above using it, and the Obj-c code as a starting point.
Also, beware, SO is not a "tutorial" site, Xcode is a complex beast and you may need to spend some time exploring other resources to overcome issues you encounter

Cleanest & safest way to include prepopulated .sqlite file in Swift app

The file needs to be read and write later. On Android I used Room & RoomAssetHelper.
I understand the basic logic that I need to include it in the project assets and then copy it to somewhere accessible for the app at first start. But I want to avoid writing these things manually and risking making an error (I am not too confident with reading files & DBs).
All of the answers that I find are from people giving quick & dirty advice on how to manually code the logic for this. I would like to do it on a clean & professional level.
Is there a library that would do most of the "risky" work for me?
(Meaning import & copy the .sqlite file, so I can start using it in my code)
I found GRDB.swift, but I cannot figure out if it supports prepopulated files.
Please stop looking for a magical library that will do all of this for you automatically.
What you need to do yourself without any SQLite library?
Add your prepopulated database.sqlite as an asset to your project.
When the app launches, check if the database.sqlite file is present at the expected location (inside your app's documents directory for example). You can check this using FileManager APIs.
If the file exists at the expected path, you are fine, no need to copy any file.
If the database.sqlite file does not exist at the expected path, you need to copy your database.sqlite file at the path using FileManager APIs.
CAUTION :
Be aware that in this step, you may encounter an error while copying the file. This should not happen for most cases. In rare caes that it does happen, you should adjust your app accordingly - indicate to user somehow that initialization failed, free some space on your phone, restart app etc.
Steps 2-4 need to be checked on every app launch - put this logic somewhere close your app startup process. If all of above instructions are followed and you succeed either via step 3 OR 4, you now have the database.sqlite file where you want it to be.
Where the SQLite library comes in?
At this point, you can use any library that suits your purpose and you feel comfortable with.
As you mentioned GRDB.swift, it allows you to specify a custom path for your database file. Copy-pasting the current version minimal setup code here for reference.
import GRDB
// 1. Open a database connection
let dbQueue = try DatabaseQueue(path: "/path/to/database.sqlite")
// 2. Define the database schema
try dbQueue.write { db in
try db.create(table: "player") { t in
t.autoIncrementedPrimaryKey("id")
t.column("name", .text).notNull()
t.column("score", .integer).notNull()
}
}
// 3. Define a record type
struct Player: Codable, FetchableRecord, PersistableRecord {
var id: Int64
var name: String
var score: Int
}
// 4. Access the database
try dbQueue.write { db in
try Player(id: 1, name: "Arthur", score: 100).insert(db)
try Player(id: 2, name: "Barbara", score: 1000).insert(db)
}
let players: [Player] = try dbQueue.read { db in
try Player.fetchAll(db)
}

Xcode: +CoreDataProperties.swift issue

I'm designing an app which is going well but I had an issue a while ago whereby I had to create a new model for CoreData because I made alterations to the Entities. I'm up to the fourth version and I had another issue with the app and I cleaned it. Now, this is what I'm getting:
The 'deleted' Attribute is set to NSDate
but after I try to build it again I get the following error:
I thought if I made alterations to the Entity Xcode would pick that up and alter any files accordingly! But that doesn't seem to be the case!
I've tried deleting the +CoreDataProperties.swift files and the 'Shopping List' swift file, recreating the 'Shopping List' swift file, under a different class name, and trying to build it again but I get the same error. This tells me its a CoreData issue, not a Swift issue. Obviously I need the attribute as NSDate but I'm not sure where to go from here!
The only way I can get the app to build is to comment out the 'deleted' attribute in the +CoreDataProperties.swift file and it runs fine.
I have the app running on a test iPhone 6 and the last time I made changes to the Entity I lost all the data I entered manually on the phone because of errors. The only way to get the app back up and running was to delete the app off the phone and reinstall it. I seriously don't want to go down that route again because I have nearly 450 various records on the phone.
If I leave the 'deleted' Attribute commented out when its uploaded to the app store, will it fail to upload, and will it fail to work correctly if the upload is successful?
I'd rather sort the issue before trying!
What you need to do is called light weight migrations. In app delegate you need to tell the app to look for the new version and create presistence store
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/// THIS IS THE CODE YOU NEED TO ADD
let container = NSPersistentContainer(name: "NAMEGOESHERE")
let description = NSPersistentStoreDescription()
description.shouldInferMappingModelAutomatically = true
description.shouldMigrateStoreAutomatically = true
container.persistentStoreDescriptions = [description]
// End of new code
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
This method worked for me. There are a number of tutorials out there on doing light weight migrations here and there is a stack overflow answer which is one I actually referred to when I had this problem here. By doing migrations your app shall be able to create a new persistance store and in that new store it ll change the attribute of deleted from Bool to NSdate as in the generated managedobject file. Hope this helps

Key data not storing to iCloud with NSUbiquitousKeyValueStore.defaultStore

So I have a simple goal, just to get this working. So theoretically if you ruined this.
Triggered save players
waited a bit
Deleted the app
Rebuilt (downloaded)
Triggered restore then the word "MEDO" would print to the console
But instead it is null, making me pretty sure that it is not saving to iC cloud some reason. I followed this tutorial. Perhaps it is too outdated to work?
func c_restoreCharecters()
{
let icloud = NSUbiquitousKeyValueStore.defaultStore()
println(icloud.objectForKey("username"))
}
func c_savePlayers()
{
let icloud = NSUbiquitousKeyValueStore.defaultStore()
icloud.setObject("MEDO", forKey: "username")
println(icloud.synchronize())
}
Obviously I am going to use this concept for something completely different in the future, but I have to get the basics down first!
Some other stuff:
iCloud set up in my settings:
My Entitlements file:

executeFetchRequest:error: A fetch request must have an entity

I had a project that was working fine. It had "Core Data" checked, and had the data model all set up. I only started adding a couple entities and properties tonight. When I try to run my app now, it won't even load. It just crashes on me.
Here's the error:
'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.'
I'm really scared because I don't have a backup of this and if I can't get it working I don't know what I'll do. :)
Thanks in advance!
EDIT:
I got fed up with my data, so I just copied a new blank xcdatamodel to my project and I'm going to start fresh. Thanks for the help!
My issue is I didn't use the same name for Entity and Class. Trivial solution to fix it is by giving them the same name.
If you are using MagicalRecored with Swift:
Make sure you use #objc directive in the Swift NSManagedObject subclass to make the class accessible to Objective-C code from the MagicalRecord library
#objc(MyEntity)
class MyEntity: NSManagedObject {
#NSManaged var myAttribute: Int16
}
After searching all over for a solution, what fixed it for me was doing a Clean/Build in Xcode.
Product->Clean, Product->Build, then try running it.
It seemed as if my data got corrupted, so I deleted my data model and the database in the iPhone simulator, and started fresh.
I had the same error.
For me, it is because I have added a new Model Version, but I did not set it as "Current Version". Careless me! To fix, select the xcdatamodel, click Design > Data Model > Set Current Version. The xcdatamodel file will then have a green tick.
Hopes that helps.
Also, make sure that your .xcdatamodeld file is in the "Copy Bundle Resources" phase of your Build Phases.
Here's what fixed it for me:
As I was converting to Swift 3, Xcode was giving me an error when declaring a new NSFetchRequest, saying that it needed a type. After adding the type, I did what anyone else would have assumed; if the request is typed, why specify an entity name? So, I removed it.
It actually was my mistake.
Swift 2.2:
let request = NSFetchRequest(entityName: "MyEntity")
When I first converted to Swift 3:
let request = NSFetchRequest<MyEntity>()
That was giving me an error. I ended up with this:
let request = NSFetchRequest<MyEntity>(entityName: "MyEntity")
And everything works fine. Personally, I'm not sure why it needs to have an entity name specified, if you're typing the request. Maybe they'll update that at some point (I hope)
i found this solution in the apple develper forum and it was exactly my problem!
the solutions is that the context must be defined inside the struct App.
not in the environment parameter
import SwiftUI
#main
struct CoreDataDemoApp: App {
private let context = CoreDataStack.context.
var body: some Scene {
WindowGroup {
ContentView()
.environment(\.managedObjectContext, context)
}
}
}
Check if,
the entity is present in the xcdatamodel file.
entity name used are same.
If you are using Swift 3 and Core Data's new stack syntax:
var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "MyAppModel")
container.loadPersistentStores(completionHandler: {
(storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
} else {
print(storeDescription)
}
})
return container
}()
Then you should be using this fetch syntax:
let request: NSFetchRequest<Client> = Client.fetchRequest()
I had this error on the first fetch after app launches when using different variations:
let request: NSFetchRequest<NSFetchRequestResult> = Client.fetchRequest()
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Client")
I did stumble across the same precise error upon taking my first steps into Core Data (and iOS 11 and Swift 4). I started off a book (sixth edition meant to target Swift 4 but presumably including some legacy stuff).
As suggested in the book my code was:
let fetchRequest = NSFetchRequest<ReminderData>()
let entity = ReminderData.entity()
fetchRequest.entity = entity
do {
let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
fatalError("Unresolved error")
}
It turned out that all I got from ReminderData.entity() is nil. Not sure if I did something wrong when setting up the data model or ... Apple's docs say that NSManagedObject.entity() must not be overwritten?
Long story short, the Codegen file ReminderData+CoreDataProperties.swift did include the solution:
#nonobjc public class func fetchRequest() -> NSFetchRequest<ReminderData> {
return NSFetchRequest<ReminderData>(entityName: "ReminderDB")
}
which was all I had to use to end-up with a proper NSFetchRequest, no fiddling with the NSEntityDescription, problem gone!
let fetchRequest = NSFetchRequest<ReminderData>(entityName: "ReminderDB")
do {
let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
fatalError("Unresolved error")
}
I built clean, and that didn't fix it. Then I deleted the app, and that didn't fix it. Then I built clean and deleted the app AT THE SAME TIME, and that fixed it.
Just add the same problem. I copied all my entities. Deleted the data model, recreated an empty one and pasted the entities back into the new data model. Solved my issue.
First I downloaded the app's data through the Organizer (to see what was happening) and noticed that it offered me to save it under a previous project name. This puzzled me. So I exited XCode 4.6.1, deleted the app (and its data) from my iPhone, and came back.
This time I got an error saying Cannot create an NSPersistentStoreCoordinator with a nil model. So I looked into the AppDelegate.m file and changed the URLForResource in the - (NSPersistentStoreCoordinator *) persistentStoreCoodinator method. It was set to the name of my app, and I changed it to 'Model' so as to match the name of my Model.xcdatamodeld.
It's working now.
This happened to me when I was fetching from the wrong database. My application has 3 sqlite databases, and of course 3 ManagedObjectContext instances. Well I was submitting the wrong ManagedObjectContext to a method asking it to query a table that didn't exist in the ManagedObjectContext I submitted. After using the correct ManagedObjectContext, all was good.
I think the original question/problem, and also the issue that most of these answers fixes (just in different ways) is just a real simple one:
Anytime you modify your core data (like adding an entity as you mention), you either have to delete all existing data (if you haven't published your app yet), or add a new version to your model.
Just thought I would post this answer, even though this is an older question, because this answer seems pretty obvious and so far hasn't been discussed in any of the questions or comments I read above.
You can also use setter method from CoraData ... Just do something like this...
On your CustomCoreDataManager.m
import "ObjectiveRecord.h"
call init method like this
(instancetype)init {
self = [super init];
if (self) {
[[CoreDataManager sharedManager] setModelName:#"YourModelName"];
}
return self; }
Hope this helps to someone...
Maybe you are trying to load a Database from a different/the wrong bundle?
For instance from or within a Framework?
I had this issue and solved it by loading the DB from the bundle of the related Framework. And then it all worked fine!!
Swift 4 + MagicalRecord:
let frameworkBundle = Bundle(for: AClassFromTheFramework.self)
let managedObjectModel = NSManagedObjectModel.mergedModel(from: [frameworkBundle])
MagicalRecord.setShouldAutoCreateManagedObjectModel(false)
NSManagedObjectModel.mr_setDefaultManagedObjectModel(managedObjectModel)
MagicalRecord.setupCoreDataStack(withAutoMigratingSqliteStoreNamed: "db.sqlite")
And voila !
I faced same issue, actually i was calling MyEnty instead of MyEntity so please re-check what names you have given to your entities and call the same and also check whether you are calling same attributes that you have defined like name
In my case, it was because this dropdown was not set to "Current Product Module" in the Data Model Inspector in Xcode (13.4.1):
Once I set that, it stopped crashing.
Hope this helps!