Confusion about selecting the suitable ORM?

Question

I use ASP.NET with a informix database.

I use a set of written classes to handle the connections, the CRUD operations, transactions, etc....

Now, I feel these classes are not the best choice, less performance,take a lot of time and have many drawbacks.

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I want to use an ORM, but I don't know how to choose the one which suits my web applications (ASP.NET, Informix).

Please help to select the convenient ORM.

I'm confused among nHibernate, Entity Framework, LINQ To SQL, and the Open Access (Telerik Component).

Note: I will use Visual Studio 2012 so I want the recent comparison.

Answer 1

I'd really suggest Entity Framework, as it is the native framework of .NET. Here it is stated that an Informix provider is available for EF.

Answer 2

Have you thought about using Fluent NHibernate? There's a wealth of articles on the web for it, and plenty on SO!! Here's one such article : converting to Fluent NHibernate sessionmanager.

EDIT :

Been thinking about your situation and I'll tell you how I usually think. Firstly, I'll think about exactly what it is I want my Gateway layer to do (this is the layer I use to talk to the persistance medium). Now, most will say, I want it to talk to the database or I want to insert and update stuff. But recently, I have found this isn't enough! Halfway through coding a gateway layer with these questions in mind, I suddenly realised that I wanted to do something ever so slightly different, and boom, I couldn't do it using NHibernate very easily. So, I made a few concessions and went with Linq-ToSql as it supported what was a higher priority requirement over some of the niceties of NHibernate.

Now, the reason for my tale is this : NHibernate provides some great little features like Result Transformation. I can have a view on my Db with masses of joined tables, giving an aliase for each field and with a lovely result transformer, bang, it's instantly transformed into my DTO. Now, don't get me wrong, Linq-To-Sql has a similar thing with the auto-generated classes. But I don't want these visible outside of the gateway layer (another conversation). Equally, Linq-To-Sql handles transactions with ease - something I thought NHibernate didn't do so well!

So, it all boils down to : what are my EXACT requirements within my gateway/repository layer and what technologies are compatible with my persistance medium?! And now, I can think about what technology I want to use.

I realise I may not have answered your question per se, but I hope it has given you something to think about!

Happy coding, Cheers,
Chris.