I'm trying to rename a core data entity (not an attribute) using Swift, iOS 13.0+. I currently have a Core Data Entity named Image, but since SwiftUI has a reserved view under that name, I'm trying to rename the entity to FileImage.
I have followed this post, but the data under that entity no longer remains on the device/mapped to the new entity. Any advice on how to rename a Core Data Entity without losing the data in that entity?
To rename CoreData entity:
Firstly set hash modifier and Renaming ID for your entity. Renaming ID should match the previous name of entity.
Select your .xcdatamodel in file navigator
Select "Add model version"
Expand .xcdatamodel in file navigator:
In file properties select a new version of .xcdatamodel:
Then rename entity name and entity class name:
After this you should rename your entity in all project.
Posting here for anyone else who needs to rename CoreData Entities (in order to avoid conflicts with SwiftUI reserved names).
Change the name of the class name for the entity (under Class in the Data Model Inspector), but do not change the name of the Entity.
You'll now have to change the name of the entity used throughout the code to the new updated class name. (FileImage -> Image), but the CoreData will no longer be in conflict with the SwiftUI reserved keyword, while maintaining all your data.
Related
I have an entity in Core Data. In the configuration section of the model, the class for the entity is specifically defined as MyModule.MyEntityName. Now I want to change MyModule to a different name, such that the class will be MyOtherModule.MyEntityName. Can I just change it and it will be fine for those updating or will I need to add some sort of migration?
Things that affect the entity version are:
...the name of the entity, the version hash of the superentity (if present), if the entity is abstract, and all of the version hashes for the properties.
Changing the class name should be fine, but as always, make sure to test it yourself before releasing the code to users.
In my current model version I have this 4 Entities :
Satellite (with relationship to one to SatelliteAnimation)
SatelliteAnimation
Radar (with relationship to one to RadarAnimation)
RadarAnimation
In my App I have different blocs in which I display information.
This is why I have entities RadarAnimation and SatelliteAnimation, in order to recognize those blocs by type.
Anyway, my issue is that I want to migrate 2 blocs in 1.
And instead of having 4 Entities, I would like to have :
Radar
Satellite
Animations
I don't need the relationships anymore.
I know I can rename an Entity in a lightweight migration process.
What I would like to do is :
Create a new data model version
Delete the SatelliteAnimation entity
Delete the relationship between Satellite and SatelliteAnimation
Delete the relationship between Radar and RadarAnimation
Rename the entity RadarAnimation by Animations
Set the new data model version as current model version
Does this way of handling my issue will affect the migration process ?
Can I rename and remove relationships in a new data model version ?
This should be possible with automatic lightweight migration. Deleting entities and relationships just works with no extra steps, so that's fine.
To rename something you'll use the renaming identifier in the model editor. After you create the new version of your model, select the entity you want to rename in the model editor. Change its name but set the renaming identifier to the old name. In your case, change the entity name from RadarAnimation to Animation, but then also set the renaming identifier on the entity to RadarAnimation so Core Data knows what it used to be called.
Incidentally attributes and relationships can also have renaming identifiers, so they can also be renamed this way.
Apple provides detailed documentation on what can be done with lightweight migration which will probably be useful as you go through this.
I am working with CoreData, on an entity called "RoleName".
The problem is: I click on "Create NSManagedObject subclass" from within my model, and so it automatically creates the classes for my entity.
However, on the declaration of the class, I get this error:
Invalid redeclaration of "RoleName"
even though I don't have any other class with the same name.
This is because Xcode handles all that by itself. I felt it like a bit of trouble as the auto generated classes don't have all my properties.
So follow these steps to get this as it used to be:
Delete what ever classes you already made for core data.
Set class.Module as Current Product module
Set Class.codegen as Manual/None
Now select your entity and create NSmanagedobject subclass
You are all set
From Apple : Whats new in Core Data
Xcode automatic subclass generation
Xcode now supports automatic generation of NSManagedObject subclasses in the modeling tool. In the entity inspector:
Manual/None is the default, and previous behavior; in this case you should implement your own subclass or use NSManagedObject.
Category/Extension generates a class extension in a file named like ClassName+CoreDataGeneratedProperties. You need to
declare/implement the main class (if in Obj-C, via a header the
extension can import named ClassName.h).
Class Definition generates subclass files named like ClassName+CoreDataClass as well as the files generated for
Category/Extension.
The generated files are placed in DerivedData and rebuilt on the first build after the model is saved. They are also indexed by Xcode,
so command-clicking on references and fast-opening by filename works.
You don't need to manually create subclasses for NSManagedObjects.
I would suggest that you delete the files that you created with NSManagedObjects (Move them to Trash) and go to every entity in the DataModel Inspector under Codegen select : Manual / None and create than the Subclasses.
Using Xcode 6.2 and CoreData. I needed to rename a couple of entity names and recreate the NSManaged objects and noticed that the New Managed objects did not get named the same as the new entity names - the old name was used.
Here's some output from diff on the data model contents file:
- <entity name="SavedSignSets" representedClassName="SavedSignSets" syncable="YES">
+ <entity name="SavedSignSet" representedClassName="SavedSignSets" syncable="YES">
This a bug or am I doing something wrong?
UPDATE:
Exact problem is this:
I had an existing entity and corresponding managed object generated by Xcode 6.2. Entity and managed object had the same name.
I changed the Entity name.
I trashed the corresponding managed object files.
Using Xcode 6.2 I generate Managed Object for the entity - assuming the new name will be used
Xcode names the managed object using the old entity name.
select the entity and check the entity inspector in the utilities view's data model inspector (the left left menu), each entity has a name field and a class field. When you change the name in the GUI you only change the class name. To correct the error you to change the name as well.
The core data framework is a little finnicky in XCode. It has seemed to get confused in overwriting existing auto-generated files. I can't guarantee this is a fix, but you can try manually trashing your old Managed Object class file(s) from the XCode Navigation window (make sure you delete, and not just remove reference), and then creating the NSManagedObject subclass again under the guise of it being a new file.
In doing this, also manually check that any Relationship references in other files get updated with the new class name as well (sometimes they will load as the generic NSManagedObject class on one side of the relationship). It was taught to me as standard practice to trash the whole set of generated entity files and recreate them as a group.
(Also, I'm running XCode 6.1.1 so I'm not on your exact version)
I am having an issue using Core Data modeler. I had an issue where I needed to change the names of entities in the modeler. When I did so, I deleted the associated managed object subclasses, did a clean, then went back the modeler, highlighted the entities with the new names, then generated subclasses using
Editor > Create NSManagedObject Subclass
When I did so, the newly generated subclasses still have the original names. Am I missing something?
In the model editor, you set the class name separately from the entity name. They don't have to be the same. If you only change the entity name name, what you're seeing is normal.
Select the ENTITY you want to change
Select Data Model from right hand top corner as shown below, and change as u want. Entity name and Class no need to be the same.
Finally Clean and Build the project.