LINQ to Cosmos DB Data

This article illustrates using LINQ to access tables within the Cosmos DB via the CData ADO.NET Data Provider for Cosmos DB. To achieve this, we will use LINQ to Entity Framework, which facilitates the generation of connections and can be seamlessly employed with any CData ADO.NET Data Providers to access data through LINQ.

See the help documentation for a guide to setting up an EF 6 project to use the provider.

1. In a new project in Visual Studio, right-click on the project and choose to add a new item. Add an ADO.NET Entity Data Model.
2. Choose EF Designer from Database and click Next.
3. Add a new Data Connection, and change your data source type to "CData Cosmos DB Data Source".

4. Enter your data source connection information.

   To obtain the connection string needed to connect to a Cosmos DB account using the SQL API, log in to the Azure Portal, select Azure Cosmos DB, and select your account. In the Settings section, click Connection String and set the following values:

   • AccountEndpoint: The Cosmos DB account URL from the Keys blade of the Cosmos DB account
   • AccountKey: In the Azure portal, navigate to the Cosmos DB service and select your Azure Cosmos DB account. From the resource menu, go to the Keys page. Find the PRIMARY KEY value and set AccountKey to this value.

   Below is a typical connection string:

   AccountEndpoint=myAccountEndpoint;AccountKey=myAccountKey;

👁 Required connection properties for the data source. (QuickBooks is shown.)

5. If saving your entity connection to App.Config, set an entity name. In this example we are setting CosmosDBEntities as our entity connection in App.Config.
6. Enter a model name and select any tables or views you would like to include in the model.

Using the entity you created, you can now perform select , update, delete, and insert commands. For example:

CosmosDBEntities context = new CosmosDBEntities();

var customersQuery = from customers in context.Customers
 select customers;

foreach (var result in customersQuery) {
 Console.WriteLine("{0} {1} ", result.id, result.City);
}

See "LINQ and Entity Framework" chapter in the help documentation for example queries of the supported LINQ.