core-data | Sample code for the objc.io Core Data book | Learning library

Need to split the 3rd row and have it in the below xml format.

My Excel data:

My XML data:

The problem has been solved by 'hackingwithswift' website

Just follow the steps on the link! "https://www.hackingwithswift.com/books/ios-swiftui/one-to-many-relationships-with-core-data-swiftui-and-fetchrequest"

original ask

I would like to use elements of [relationship]
But whatever I try, it doesn't work..
There is something, what I missed and, sadly I don't know what that would be until now :/

First of all, I want to show my core data model and code.

Core Data Model Image

Entity: Page, Attribute: name(String), relationship: toCard
Entity: Card, Attribute: title(String), price(Double), relationship: toPage

Scenario: Page has multiple cards
One to Many (One page to many cards)

I have an app that heavily uses Measurements. It is written in SwiftUI/iOS 14. I persist the data in a Core Data database. The app is working fine, until I try to implement secure coding. I made a sample app to strip everything away except the basics. It is based off of Xcode's default Core Data app with few changes. Again, I can save my measurement fine until I try to use secure coding.

The xddatamodel, as well as the errors, is as follows:

I am using a manual codegen for the Entity and it looks like this:

I have a class A that has a "to many" relationship with B. A and its Bs are fetched from a REST endpoint, we use this approach to create the objects.

A has a unique ID and some other properties (not shown in the example). B has an ID (bID) that is unique when combined with A, and a relationship to A called a. For A the constraint is "uniqueID". For B, the constraint is "a, bID" - we want each B to only exist for each combination of A and bID. The delete rule for A to its Bs is "Cascade". The merge policy for the context and all child contexts is NSOverwriteMergePolicy.

The code looks something like this:

The question is this: how do you group Core Data objects by attribute and then perform simple calculations (let's say, sum) on them?

I've found a few similar answers for this (like this one), but none seem conclusive and all are geared up towards Swift (whereas I am working on SwiftUI).

For example, I have a Core Data model that looks like this:

I am trying to put a CoreData model into a Swift Package to extract my model code / classes from my main codebase.

I have done the following to recreate the issue I'm having from scratch:

• Create a new swift package called SampleModelPackage (File -> New -> Swift Package)
• Created a Core Data Model Definition File (Create File -> New -> File | iOS -> Core Data -> Data Model)
• Saved it in the Sources/SampleModelPackage directory alongside the auto-generated SampleModelPackage.swift

Now - when I attempt to open the Model.xcdatamodelId file in Xcode, it just shows me a "Version" icon (see screenshot), whereas creating a Core Data Model file in a Project or Framework will allow me to edit the model.

The second / follow up question would be how would I then extend the code-gem'd model files as normal? And how would I load that model definition (normally I would use a Bundle ID and the model file name)

I have tried adding the model file to the resources array of the Package.swift file (using .process and using .copy) as described on this page: https://developer.apple.com/documentation/swift_packages/bundling_resources_with_a_swift_package

Or more generally, is this even possible? (this article https://ishabazz.dev/blog/2020/7/5/using-core-data-with-swift-package-manager seems to imply that packaging core data models like this is possible)

(I am using Xcode 12.4)

I have a simple core-data/swiftui test app with 2 entities. 1: Item entity with a simple text and timestamp attributes. And a one-to-one relationship to an Editor entity. 2: editor entity with a name attribute and a one-to-many relationship to Item. In the item view I want to pick an editor from a list of stored Editors. However when I update the view (i.e. adding text to the text attribute), the list of editors to pick from grows with new and empty editor objects.

I am a newbie to SwiftUI but making reasonable progress. I am using the latest version of Xcode 12.4 and running BigSur 11.2.1. I am at the stage where I want to use core-data but have run into an issue that I can't find a fix.

When I create the basic Xcode project I select App and macOS as the template Then I select Interface - SwiftUI, Life Cycle - SwiftUI App, Language - Swift and select Use Core Data

A new project is created and Builds and Runs without any issues. In the window that appears I can add a new item (a datestamp) by simply clicking the + Button on the top bar. So far so good. This is all vanilla apple code.

Where I am stuck :- The List - ForEach View in the ContentView won't allow any of the Entities (items) to be selected by clicking and therefore I can't find a way to delete an entry.

If I replace the Entities with an array of Text items then I can select them and delete them by using @State var selectKeeper = Set() with a selection: $selectKeeper in the List View.

Can someone please explain how to do it?

This is the vanilla code for the content view.

I'm trying to follow this tutorial:

https://www.avanderlee.com/swift/valuetransformer-core-data/

But I'm stumped on where (and how!) exactly to use