Updata NSManagedObject class definition from datamodel

Question

Being fairly new to CoreData (Started playing with it 2 hours ago ;) ) I keep wondering if there is an easier way to do things.

I'm currently using a DataModel to create my persistant objects code.

However when I keep adjusting things like number of attributes sotred, the name of the fields etc... and that leads to having the update the code of my NSManagedObjects.

I found that you can create the classes with the attributes already implemented, however, I haven't figured out how to update the code of an existing class other than adding it by hand or creating a new object and overwriting the existing one? (or how do other developers do it)

I'm aware that the answer is surely: "there is no better way" but I still have to ask.

I hope there is no better way hehehe (as I have spent a lot of time with this too...) I will follow this post! Thanks for asking. — Ricard Pérez del Campo, Apr 18 '12 at 09:12

score 2 · Accepted Answer · answered Apr 18 '12 at 09:12

2

Check out mogenerator.

This command line utility will generate two class files. A machine generated _MyClass header and implementation, with all code for your model. It will also create a subclass MyClass where you can add your own customizations.

Each time you regenerate your code, only the machine generated _MyClass files will be updated. All your changes to MyClass will be preserved.

answered Apr 18 '12 at 09:12

Joris Kluivers

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Nice Solution, However the code that is generated doesn't work if your using ARC because of the "struct", any ideas on that (a part from deactivating the ARC) – Jason Rogers Apr 18 '12 at 09:56
1

Yes, mogenerator has an option to enable ARC in templates. Use ` --template-var arc=true` at the command line. – Joris Kluivers Apr 18 '12 at 10:08
Got a couple questions : where is the doc of mogenerator ? how can i create custom init ? – Jason Rogers Apr 18 '12 at 13:43
I always refer to the README or [the source on github](https://github.com/rentzsch/mogenerator) – Joris Kluivers Apr 18 '12 at 13:57

score 1 · Answer 2 · answered Apr 18 '12 at 17:12

If you can not use mogenerator, you can use the native code generation. Make sure you regenerate the code every time. However, that will erase any changes.

So, you have two very viable options.

Write a category on the entity class. You can do just about everything you want with a category.
Subclass from the entity, and put all your code in there.

Personally, I prefer using categories unless I absolutely must inherit... which is extremely rare.

Updata NSManagedObject class definition from datamodel

2 Answers2