SwiftData: How to make a copy of a model containing an array of other models

@priamos23 HWS+

Feb '24

In SwiftData I have a @Model class for a log. This has a name and some other attributes, but most importantly an array of LogEntry. Log Entries are also @Model class. So:

@Model class Log { var name: String = "" ... @Relationship(inverse: \LogEntry.log) var logEntries: [LogEntry] = [] }

@Model class LogEntry { var name: String = "" ... var log : Log? = nil }

My question is: How do I make a complete copy of a log? I'd like to be able to write:

var log = Log(name: "Log 1", [ LogEntry(name: "Log Entry 1"), LogEntry(name: "Log Entry 2") ] ) modelContext.insert(log)

and then somewhere later: var logCopy = Log(basedOnLog: log) And this new object should also contain a copy of all log entries in its logEntries array.

To be honest, I feel a little stupid. Because deep copying a class I have basically learned back in the C/C++ days some decades ago. But I am really stuck here. Any help is highly appreciated! How does the initializer or a copy function look like so that it works in SwiftData?

Thanks a lot!

Kind regards Stefan

@ygeras

Feb '24

Suppose this article will answer your question. Not sure if it works with @Model though... but give it a try.

https://www.hackingwithswift.com/example-code/system/how-to-copy-objects-in-swift-using-copy

@david112267

Feb '24

yes this is very good

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