A recommended ORM tool for asp.net or help with SubSonic3 simple repository

Question

Hi,

I'm wanting to use an ORM tool for an asp.net web app I'm working on. I've put together all my classes and just want to have the data persisted. I downloaded SubSonic 3.0 and began using the simple Repository...which was brilliant. I'm new to ORM tools as my first experience commercially was the DataSets/Stored Procs world for a few years which I'm trying to move on from (even just academically)...anyway, the simple repository was so easy to use...except I'm stuck when it comes to data relationships. I was hoping to have a list property that would be persisted as two tables with a foreign key relationship etc...

I've seen that I could manually add the extra foreign key Id's to objects but am now wondering whether I should go for a different ORM tool, as there seems to be a lot...any help much appreciated!

Note: I've heard that nhibernate will do pretty much anything, but looking at some "start guides" it seemed a world of extra learning and time compared to the SubSonic 3.0 Simple Repository...But if that simplicity isn't available for what I'm after, I'll learn!

edit
Thanks for all your responses and suggestions...I tried out most of the suggestions hoping to avoid nhibernate but wasn't able to...I've bought NHibernate in Action and am taking the time to learn it which I can already see as being the right decision.

Answer 1

You shouldn't exclude Entity Framework (or LINQ to SQL for that matter).

The reason I said Entity Framework over LINQ to SQL is that the Entity Framework provides the ability to create the database from an Entity diagram (which should be easy to generate from your classes).

Both of those are built in to .NET so they're immediately available with minimal hassle.

Answer 2

I really suggest NHibernate, it's not that complex at all once you get into it, and will provide you with a huge range of features instead of locking you into one mindset. I haven't looked back since I started using it, and have experienced some other ORM's but have never been amazingly impressed.

Answer 3

Mindscape's LightSpeed is generally pretty simple (it takes a convention over configuration approach), and automatically handles the list scenario you describe. Although it requires foreign key IDs under the surface, it has a designer which will take care of adding those for you (you can drag tables on, or create associations using the designer and the designer will automatically implement the foreign keys). See the getting started screencast for an example.

Answer 4

I faced your exact problem recently. SimpleRepository is fantastic if you're using single entities that arent related. If you are set on the model-first-database-second paradigm (which I was) then I would suggest Fluent NHibernate with automappings. The getting started stuff on the website will have you up and running quickly. The only gotcha is that you have to be a little careful about creating foreign relationships. Make sure both your primary entity and your reference entity both maintain a mapping to each other, otherwise NHibernate will not automatically cascade save a new reference entity you create.

Ie:

(note: list of recipes is public for sake of brevity, you probably want to create an internal field with a custom get/set properties to expose this collection in real life)

public class Recipe {

    public virtual RecipeBook RecipeBook {get; set;}
    public virtual string RecipeInstructions {get; set;}
}


public class RecipeBook {

    public virtual IList<Recipe> Recipes { get; set; }
    public virtual string BookTitle {get; set;}

    public void AddRecipe(Recipe recipe) {

         recipe.RecipeBook = this;
         Recipes.Add(recipe);
    }

}

Answer 5

Try DataObjects.Net as an alternative. It is completely different to Subsonic. Composite foreign keys, unified key & version adapters (Key and VersionInfo types + Entity.Key and Entity.GetVersion(...)), truly transparent references (Subsonic does not support references at all) and good LINQ support are just few examples of what's there.

Good starting point is introduction part (start from the tail, if you prefer to look up an example first) from its Manual.

Answer 6

NHibernate rocks. I was productive fairly quickly with it. Check out www.summerofnhibernate.com for great free training videos. They're for an older version but you should be able to figure out the differences as you go.

Answer 7

If you are using SQL server as your backend database, I would suggest using Linq to Sql and using the SQLMetal tool that ships with VS2008. You can do just about everything that NHibernate does and you dont have to lift a finger (not to mention no pesky xmls), just run a command on the VS2k8 Command line prompt. The best resource to start would be Scott Gu's introduction available here and then some SQLMetal documentation.