Is it feasable to have DAL and BLL layers in a Mac OS X Application?

It's highly-optimized for persisting objects to and from the local filesystem. It also performs validation at the model level, results caching, notifications, etc.

Not really its just that my background is building systems using databases and building multi-tiered applications in .NET. I already know how to do this and just want to apply it to Cocoa rather than having to learn a new object graph framework which is going to extend an already tight project deadline. I did look into this when I first started the development but could not find any good tutorials for what I wanted on the subject.Ie demonstrating CRUD operations with models etc. Thanks – Cragly May 3 at 20:10 I'd highly recommend taking another look at CoreData, as you'll need to build these features yourself, which takes time.

There are only a few scenarios where using it doesn't make sense. – Scott May 3 at 21:38 Have decided to go with CoreData after a good play around. As you say its highly optimized and after an initial steep learning curve its well worth it.

– Cragly May 22 at 13:41.

What you describe sounds like a good idea to me. Putting your validation and business logic in your model classes is proper use of MVC, and having the data stored in an sqlite database (that the model classes talk to) is a commonly used methodology too. I'm not sure if we're on the same page with terminology: if you use that design, your classes "that undertake business/data access logic (to a sqlite database) that can then be called from any controller" will in fact be model classes.

However if this functionality doesn't belong in a model class but in a controller then I could possible have code duplication in other controllers that want to get a list of users. Hope this makes sense. – Cragly May 3 at 18:10 1 You could have a single class for fetching, treated like a singleton.

To use it (from your controller) you feed in some parameters and it returns a bunch of your model objects. Thus there's no code duplication because any controller that needs to fetch users can just talk to that singleton. Alternatively, just make a class method (as opposed to an instance method) on The User class that fetches data then creates and instantiates User objects.

Both these approaches can be found in Apple APIs. – Amorya May 3 at 23:37.

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