Andrew Theken's C# Blog

As promised in my previous post, I am going to introduce you to a project that I’ve been working on with a great team of people on GitHub.

NoRM is a .net library to interact with the document-oriented database MongoDB. We set about doing this in a way that makes sense for the C# developer who doesn’t want to spend an inordinate amount of time configuring the database. As you’ll see in a moment, with NoRM, there’s very little you need to do to get started with MongoDB.

NoRM stands for “No Object-Relational Mapping” – it seems that people are concerned about leaving relational databases because they’ll lose the low-friction environments they’ve come to expect (think ‘LINQ-to-SQL’). Another concern around moving to a NoSQL option is the notion that these datastores carry little or no structure. By creating a strongly-typed interface to MongoDB, I feel that we have addressed both of these concerns.

So, just to whet your appetite, here’s an example of how you’d use NoRM to store some widgets.

//First, define your document (this can be very similar to your concept of "Model" -- notice there's no special attributes or configuration.)
public class Widget
{
public ObjectId Id {get;set;}
public String Color {get;set;}
public double Price {get;set;}
public DateTime ReleaseDate {get;set;}
public IEnumerable Reviews {get;set;}
}
//Next, spool up a connection to your database 
//(The DB doesn't have to exist yet, but MongoDB DOES need to be running)
using(var db = Mongo.Create("mongo://localhost/ProductDB")
{

//Get a reference to the collection in which we want to 
//store our Widgets (doesn't have to exist yet.)
var widgets = db.GetCollection();

//create a widget instance.
var topSellingWidget = new Widget{ Id = ObjectId.NewObjectId(), Color = "Red", Price = 39.95,
ReleaseDate = DateTime.Now, Reviews = Enumerable.Empty() };

//now, save the instance
widgets.Save(topSellingWidget);

//lastly, retrieve it from the DB.
var hydratedTopSellingWidgetFromDB = widgets.FindOne(new {Color = "Red",Price = 39.95});
}

That’s just a taste of the simplicity that is NoRM, there’s a huge amount of functionality that I’m not covering including:

• Fluent configuration
• Solid LINQ support
• Advanced update capabilities (update single or multiple documents that match template documents)
• Map/Reduce functionality.
• Support for MongoDB operators via the “Q” (Qualifiers) and “M” (Modifiers) classes.
• If you need it, “Weakly-typed” interaction via the “Expando” class.
• Bulk-insert capability (a la SqlBulkCopy)

Aside from actual “features”, there are lots of elements that make software good, here’s a few things I think make NoRM awesome:

• Tests: We have more than 400 tests that verify the functionality found in NoRM, and although we have just reached the v0.9.0 milestone, the library is very stable, and I am aware of production deployments using NoRM, today.
• Participation: I started NoRM in the last few days of January 2010, and have seen incredible participation from the Open Source community – I’ve learned a lot about what people do — and don’t — need in a library, and some of the interesting pieces of helping to shape an Open Source project (hopefully I can share that in another blog post). We have a vibrant community at http://groups.google.com/group/norm-mongodb.
• Pragmatism and Experience: I am routinely impressed by the ideas and code that the project’s contributors bring forward.

Please download and use the library:

• Stable Milestone: http://github.com/atheken/NoRM/zipball/v0.9.0,
• Project Page (the master branch will always “Stable”): http://github.com/atheken/norm.

Remember that we want NoRM to be the best C# driver for MongoDB possible, so please give us feedback, either in the Google Group or follow me on twitter (@atheken).

Cheers.