I want to add an NSMutableArray of NSStrings to one of my Entities in my core data model. The problem is that this isn't a supported type in Core Data.
I tried making a tranformable attribute, but the problem is that I see no way of turning a NSMutableArray to NSData, and then going from NSData, back to an NSMutableArray. Does anyone have an idea as to how this issue can be solved?
(I know I can archive the array, but I don't want to do that, I want it to be present in my model).
To save an object with Core Data, you can simply create a new instance of the NSManagedObject subclass and save the managed context. In the code above, we've created a new Person instance and saved it locally using Core Data.
There are two steps to storing an array of a custom struct or class in Core Data. The first step is to create a Core Data entity for your custom struct or class. The second step is to add a to-many relationship in the Core Data entity where you want to store the array.
The NSMutableArray class declares the programmatic interface to objects that manage a modifiable array of objects. This class adds insertion and deletion operations to the basic array-handling behavior inherited from NSArray .
You could have a binary data attribute in your modeled object, archive the array to data, and hand it off to the object.
But I think the better way would be to have a to-many relationship, instead of using an array directly.
****Edit: Here's how to archive the array into NSData so that it can be used in your managed object***
NSData *arrayData = [NSKeyedArchiver archivedDataWithRootObject:[NSArray arrayWithObjects:@"1",@"2", nil]];
Basically, any class you have which conforms to the NSCoding protocol can be archived in this way. NSArray/NSMutableArray already conform to it. They tell all of their objects to archive themselves, so they must conform too. And all of those objects' members must conform, etc. It's like a tree.
Since your array conforms, and it's an array of NSString (which also conforms), then you're golden.
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