Azure Cosmos DB: Build a DocumentDB API web app with .NET and the Azure portal

Azure Cosmos DB is Microsoft’s globally distributed multi-model database service. You can quickly create and query document, key/value, and graph databases, all of which benefit from the global distribution and horizontal scale capabilities at the core of Azure Cosmos DB.

This quick start demonstrates how to create an Azure Cosmos DB account, document database, and collection using the Azure portal. You'll then build and deploy a todo list web app built on the DocumentDB .NET API, as shown in the following screenshot.

Todo app with sample data

Prerequisites

If you don’t already have Visual Studio 2017 installed, you can download and use the free Visual Studio 2017 Community Edition. Make sure that you enable Azure development during the Visual Studio setup.

If you don't have an Azure subscription, create a free account before you begin.

Alternatively, you can Try Azure Cosmos DB for free without an Azure subscription, free of charge and commitments. Or you can use the Azure Cosmos DB Emulator for this tutorial with a URI of https://localhost:8081 and a key of

C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==

Create a database account

  1. In a new browser window, sign in to the Azure portal.
  2. Click New > Databases > Azure Cosmos DB.

    The Azure portal Databases pane

  3. In the New account page, enter the settings for the new Azure Cosmos DB account.

    Setting Suggested value Description
    ID Enter a unique name Enter a unique name to identify this Azure Cosmos DB account. Because documents.azure.com is appended to the ID that you provide to create your URI, use a unique but identifiable ID.

    The ID can contain only lowercase letters, numbers, and the hyphen (-) character, and it must contain 3 to 50 characters.
    API SQL The API determines the type of account to create. Azure Cosmos DB provides five APIs to suits the needs of your application: SQL (document database), Gremlin (graph database), MongoDB (document database), Azure Table, and Cassandra, each which currently require a separate account.

    Select SQL because in this quickstart you are creating a document database that is queryable using SQL syntax and accessible with the DocumentDB API.

    Learn more about the DocumentDB API
    Subscription Your subscription Select Azure subscription that you want to use for this Azure Cosmos DB account.
    Resource Group Enter the same unique name as provided above in ID Enter a new resource-group name for your account. For simplicity, you can use the same name as your ID.
    Location Select the region closest to your users Select geographic location in which to host your Azure Cosmos DB account. Use the location that's closest to your users to give them the fastest access to the data.
    Enable geo-redundancy Leave blank This creates a replicated version of your database in a second (paired) region. Leave this blank.
    Pin to dashboard Select Select this box so that your new database account is added to your portal dashboard for easy access.

    Then click Create.

    The new account blade for Azure Cosmos DB

  4. The account creation takes a few minutes. During account creation the portal displays the Deploying Azure Cosmos DB tile.

    The Azure portal Notifications pane

    Once the account is created, the Congratulations! Your Azure Cosmos DB account was created page is displayed.

Add a collection

You can now use the Data Explorer tool in the Azure portal to create a database and collection.

  1. Click Data Explorer > New Collection.

    The Add Collection area is displayed on the far right, you may need to scroll right to see it.

    The Azure portal Data Explorer, Add Collection blade

  2. In the Add collection page, enter the settings for the new collection.

    Setting Suggested value Description
    Database id Tasks Enter Tasks as the name for the new database. Database names must contain from 1 through 255 characters, and they cannot contain /, \, #, ?, or a trailing space.
    Collection id Items Enter Items as the name for your new collection. Collection ids have the same character requirements as database names.
    Storage capacity Fixed (10 GB) Change the value to Fixed (10 GB). This value is the storage capacity of the database.
    Throughput 400 RU Change the throughput to 400 request units per second (RU/s). If you want to reduce latency, you can scale up the throughput later.
    Partition key /category A partition key that distributes data evenly to each partition. Selecting the correct partition key is important in creating a performant collection. To learn more, see Designing for partitioning.

    Click OK.

    Data Explorer displays the new database and collection.

    The Azure portal Data Explorer, showing the new database and collection

Add sample data

You can now add data to your new collection using Data Explorer.

  1. In Data Explorer, the new database appears in the Collections pane. Expand the Tasks database, expand the Items collection, click Documents, and then click New Documents.

    Create new documents in Data Explorer in the Azure portal

  2. Now add a document to the collection with the following structure.

    {
        "id": "1",
        "category": "personal",
        "name": "groceries",
        "description": "Pick up apples and strawberries.",
        "isComplete": false
    }
    
  3. Once you've added the json to the Documents tab, click Save.

    Copy in json data and click Save in Data Explorer in the Azure portal

  4. Create and save one more document where you insert a unique value for the id property, and change the other properties as you see fit. Your new documents can have any structure you want as Azure Cosmos DB doesn't impose any schema on your data.

    You can now use queries in Data Explorer to retrieve your data. By default, Data Explorer uses SELECT * FROM c to retrieve all documents in the collection, but you can change that to a different SQL query, such as SELECT * FROM c ORDER BY c._ts DESC, to return all the documents in descending order based on their timestamp.

    You can also use Data Explorer to create stored procedures, UDFs, and triggers to perform server-side business logic as well as scale throughput. Data Explorer exposes all of the built-in programmatic data access available in the APIs, but provides easy access to your data in the Azure portal.

Clone the sample application

Now let's switch to working with code. Let's clone a DocumentDB API app from GitHub, set the connection string, and run it. You'll see how easy it is to work with data programmatically.

  1. Open a git terminal window, such as git bash, and CD to a working directory.

  2. Run the following command to clone the sample repository.

    git clone https://github.com/Azure-Samples/documentdb-dotnet-todo-app.git
    
  3. Then open the todo solution file in Visual Studio.

Review the code

Let's make a quick review of what's happening in the app. Open the DocumentDBRepository.cs file and you'll find that these lines of code create the Azure Cosmos DB resources.

  • The DocumentClient is initialized on line 78.

    client = new DocumentClient(new Uri(ConfigurationManager.AppSettings["endpoint"]), ConfigurationManager.AppSettings["authKey"]);
    
  • A new database is created on line 93.

    await client.CreateDatabaseAsync(new Database { Id = DatabaseId });
    
  • A new collection is created on line 112.

    await client.CreateDocumentCollectionAsync(
        UriFactory.CreateDatabaseUri(DatabaseId),
        new DocumentCollection { Id = CollectionId },
        new DocumentCollection
            {
               Id = CollectionId,
               PartitionKey = new PartitionKeyDefinition() { Paths = new Collection<string>() { "/category" } }
            },
        new RequestOptions { OfferThroughput = 1000 });
    

Update your connection string

Now go back to the Azure portal to get your connection string information and copy it into the app.

  1. In the Azure portal, in your Azure Cosmos DB account, in the left navigation click Keys, and then click Read-write Keys. You'll use the copy buttons on the right side of the screen to copy the URI and Primary Key into the web.config file in the next step.

    View and copy an access key in the Azure portal, Keys blade

  2. In Visual Studio 2017, open the web.config file.

  3. Copy your URI value from the portal (using the copy button) and make it the value of the endpoint key in web.config.

    <add key="endpoint" value="FILLME" />

  4. Then copy your PRIMARY KEY value from the portal and make it the value of the authKey in web.config. You've now updated your app with all the info it needs to communicate with Azure Cosmos DB.

    <add key="authKey" value="FILLME" />

Run the web app

  1. In Visual Studio, right-click on the project in Solution Explorer and then click Manage NuGet Packages.

  2. In the NuGet Browse box, type DocumentDB.

  3. From the results, install the Microsoft.Azure.DocumentDB library. This installs the Microsoft.Azure.DocumentDB package as well as all dependencies.

  4. Click CTRL + F5 to run the application. Your app displays in your browser.

  5. Click Create New in the browser and create a few new tasks in your to-do app.

    Todo app with sample data

You can now go back to Data Explorer and see query, modify, and work with this new data.

Review SLAs in the Azure portal

The throughput, storage, availability, latency, and consistency of the resources in your account are monitored in the Azure portal. Let's take a quick look at these metrics.

  1. Click Metrics in the navigation menu.

    Metrics in the Azure portal

  2. Click through each of the tabs so you're aware of the metrics Azure Cosmos DB provides.

    Each chart that's associated with the Azure Cosmos DB Service Level Agreements (SLAs) provides a line that shows if any of the SLAs have been violated. Azure Cosmos DB makes monitoring your SLAs transparent with this suite of metrics.

    Azure Cosmos DB metrics suite

Clean up resources

If you're not going to continue to use this app, delete all resources created by this quickstart in the Azure portal with the following steps:

  1. From the left-hand menu in the Azure portal, click Resource groups and then click the name of the resource you created.
  2. On your resource group page, click Delete, type the name of the resource to delete in the text box, and then click Delete.

Next steps

In this quickstart, you've learned how to create an Azure Cosmos DB account, create a collection using the Data Explorer, and run a web app. You can now import additional data to your Cosmos DB account.