Good database library/ORM for cocoa development

Question

I am developing a cocoa application that will be making heavy use of both web services and a standard dbms (most likely MySQL) and I am wondering if anyone has a good option for a database library or ORM solution they have used. CoreData is not an option due to the need to support a standard DBMS and to be able to modify the data outside of the normal application operation.

I have found a number of possible options from new open source libraries: http://github.com/aptiva/activerecord/tree/master

To writing my own wrapper for the C MySQL api.

Any advice is welcome,

Thanks!

Paul

Answer 1

GDL2 is a nice example, based on EOF.

Answer 2

I've also implemented a simple object persistence framework based on sqlite, but it certainly wasn't trivial to do. I agree with eJames' conclusion- don't implement one yourself if you don't have to.

If you aren't committed to programming in Objective-C you might want to take a look at PyObjC which would allow you to program the database portion in Python. You can use the MySQLdb module for DB access and there are plenty of tutorials online for its use. It isn't hard to stuff the data back into Cocoa/CF classes and pass them back to your app.

The main caveat with PyObjC is that at the moment it doesn't work with Tiger.

Answer 3

You might also want to check out the BaseTen framework. It is a Core Data-like framework (in fact, it can import Core Data models), but works with PostgreSQL (though not MySQL, as far as I know). It includes some very nice features such as schema discovery at run time. It also includes an NSArrayController subclass that automatically handles locking and synchronizing across multiple users, so you can continue to make use of Apples Key-value Binding in your UI.

Answer 4

Instead of reinventing the wheel by writing your own communication wrapper to deal with MySQL from Cocoa, you could try the SMySQL framework (a.k.a. MCPKit), it was part of the CocoaMySQL application that evolved into the Sequel Pro project. It works with varying versions of MySQL, and seems to be quite robust.

If you need to understand how to incorporate it into your application, there's not much documentation around, but it has an easy to understand interface and you can see it working by looking at the source of Sequel Pro, which is downloadable from Google code.

There is also the CocoaMySQL-SBG fork of the CocoaMySQL project, but that seems to be out of date and I couldn't get it to build properly.

Answer 5

We faced a similar question when we first started work on Checkout, our solution was to code the entire app in Python, using PyObjC.  Checkout 1 had an sqlite backend, Checkout 2 has a postgres backend.

There are a couple of really mature and powerful ORMs on the Pyton side, such as SQLObject, which is pretty simple to work with (we used it for Checkout 1.0) and SQLAlchemy, which is more powerful but a bit harder to wrap your brain around (we used it for Checkout 2.0).

One approach you could evaluate, is building the application in Objective-C, but writing the data model and database connectivity/adminstration code in Python. You can use PyObjC to create a plugin bundle from this code, that you then load into your app  That's more or less the approach we took for Checkout Server, which uses a Foundation command-line tool to administer a postgres server and the databases in it, this CLI tool in turn loads in a Python plugin bundle that has all of the actual database code in it.  End-users mostly interact with the database through a System Preferences pane, that has no clue what the database looks like, but instead uses the command-line tool to interact with it.

Loading a plugin is simple:

NSBundle *pluginBundle = [NSBundle bundleWithPath:pluginPath];
[pluginBundle load];

You will probably need to create .h files for the classes in your bundle that you want to have access to from your Obj-C code.