In one of the previous blog posts, I introduced DocumentDB?-?Microsoft’s debut into the world of NoSQL databases. You learned how it is different for being a JSON document only database. You also learned to create an instance of DocumentDB in Azure.

In the previous post, you used NuGet to install the required packages to program against DocumentDB in a .NET application. Today let’s explore some of the programming constructs to operate on an instance of DocumentDB.

First step is to create a repository to allow you connect to your instance of DocumentDB. Create a repository class and reference the Microsoft.Azure.Documents.Client namespace in it. The Database object can be used to create an instance. The following code illustrates:

Database db = DbClient.CreateDatabaseAsync(new Database { Id = DbId } ).Result; 

Here DbClient is a property of type DatabaseClient exposed by Microsoft.Azure.Documents.Client API in your repository class. It provides the method CreateDatabaseAsync to connect to DocumentDB. You need to have the following key values from your instance of DocumentDB in azure:

1. End point URL from Azure Management Portal
2. Authentication Key
3. Database Id
4. Collection name

You can create an instance of DocumentClient using the following construct:

private static DocumentClient DbClient    {        get        {            Uri endpointUri = new Uri(ConfigurationManager.AppSettings["endpoint"]);                return new DocumentClient(endpointUri, ConfigurationManager.AppSettings["authKey"];        }    }

Next you need to create a Document Collection using the method CreateDocumentCollectionAsync.

DocumentCollection collection = DbClient. CreateDocumentCollectionAsync ( Database.SelfLink, new DocumentCollection { Id = CollectionId } ).Result; 

You are now all set to perform DocumentDB operations using the repository. Note that you need to reference Microsoft.Azure.Documents.Linq to use Linq constructs for querying. Here is an example:

var results = DbClient.CreateDocumentQuery(collection.DocumentsLink); 

Note that whatever entity replaces type T, the properties of that entity must be decorated with JsonProperty attribute to allow JSON serialization.

To create an entry you can use the CreateDocumentAsync method as shown here:

DbClient.CreateDocumentAsync(collection.SelfLink, T); 

In a similar fashion, you can also use the equivalent update method to update the data in your instance of DocumentDB.

Beyond .NET, DocumentDB also provides libraries to allow using JavaScript and Node.js. The interesting aspect is it allows T-SQL style operations such as creation of stored procedures, triggers, and user defined functions using JavaScript. You can write procedural logic in JavaScript, with atomic transactions. Performance is typically very good with JSON mapped all the way from the client side to DocumentDB as the unit of storage. ?