Quickstart: Use Azure Cosmos DB for NoSQL with Azure SDK for .NET

Article
2025-04-08
Applies to: ✅ NoSQL

In this quickstart, you deploy a basic Azure Cosmos DB for NoSQL application using the Azure SDK for .NET. Azure Cosmos DB for NoSQL is a schemaless data store allowing applications to store unstructured data in the cloud. Query data in your containers and perform common operations on individual items using the Azure SDK for .NET.

API reference documentation | Library source code | Package (NuGet) | Azure Developer CLI

Prerequisites

Azure Developer CLI
Docker Desktop
.NET 9.0

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

Initialize the project

Use the Azure Developer CLI (azd) to create an Azure Cosmos DB for NoSQL account and deploy a containerized sample application. The sample application uses the client library to manage, create, read, and query sample data.

Open a terminal in an empty directory.
If you're not already authenticated, authenticate to the Azure Developer CLI using azd auth login. Follow the steps specified by the tool to authenticate to the CLI using your preferred Azure credentials.
```
azd auth login
```

Use azd init to initialize the project.

azd init --template cosmos-db-nosql-dotnet-quickstart

During initialization, configure a unique environment name.
Deploy the Azure Cosmos DB account using azd up. The Bicep templates also deploy a sample web application.
```
azd up
```
During the provisioning process, select your subscription, desired location, and target resource group. Wait for the provisioning process to complete. The process can take approximately five minutes.

Once the provisioning of your Azure resources is done, a URL to the running web application is included in the output.

Deploying services (azd deploy)

  (✓) Done: Deploying service web
- Endpoint: <https://[container-app-sub-domain].azurecontainerapps.io>

SUCCESS: Your application was provisioned and deployed to Azure in 5 minutes 0 seconds.

Use the URL in the console to navigate to your web application in the browser. Observe the output of the running app.

Screenshot of the running web application.

Install the client library

The client library is available through NuGet, as the Microsoft.Azure.Cosmos package.

Open a terminal and navigate to the /src/web folder.
```
cd ./src/web
```
If not already installed, install the Microsoft.Azure.Cosmos package using dotnet add package.
```
dotnet add package Microsoft.Azure.Cosmos --version 3.*
```
Also, install the Azure.Identity package if not already installed.
```
dotnet add package Azure.Identity --version 1.12.*
```
Open and review the src/web/Cosmos.Samples.NoSQL.Quickstart.Web.csproj file to validate that the Microsoft.Azure.Cosmos and Azure.Identity entries both exist.

Import libraries

Import the Azure.Identity and Microsoft.Azure.Cosmos namespaces into your application code.

using Azure.Identity;

using Microsoft.Azure.Cosmos;

Object model

Name	Description
CosmosClient	This class is the primary client class and is used to manage account-wide metadata or databases.
Database	This class represents a database within the account.
Container	This class is primarily used to perform read, update, and delete operations on either the container or the items stored within the container.
PartitionKey	This class represents a logical partition key. This class is required for many common operations and queries.

The sample code in the template uses a database named cosmicworks and container named products. The products container contains details such as name, category, quantity, a unique identifier, and a sale flag for each product. The container uses the /category property as a logical partition key.

Authenticate the client

This sample creates a new instance of the CosmosClient class and authenticates using a DefaultAzureCredential instance.

DefaultAzureCredential credential = new();

CosmosClient client = new(
    accountEndpoint: "<azure-cosmos-db-nosql-account-endpoint>",
    tokenCredential: new DefaultAzureCredential()
);

Get a database

Use client.GetDatabase to retrieve the existing database named cosmicworks.

Database database = client.GetDatabase("cosmicworks");

Get a container

Retrieve the existing products container using database.GetContainer.

Container container = database.GetContainer("products");

Create an item

Build a C# record type with all of the members you want to serialize into JSON. In this example, the type has a unique identifier, and fields for category, name, quantity, price, and sale.

public record Product(
    string id,
    string category,
    string name,
    int quantity,
    decimal price,
    bool clearance
);

Create an item in the container using container.UpsertItem. This method "upserts" the item effectively replacing the item if it already exists.

Product item = new(
    id: "aaaaaaaa-0000-1111-2222-bbbbbbbbbbbb",
    category: "gear-surf-surfboards",
    name: "Yamba Surfboard",
    quantity: 12,
    price: 850.00m,
    clearance: false
);

ItemResponse<Product> response = await container.UpsertItemAsync<Product>(
    item: item,
    partitionKey: new PartitionKey("gear-surf-surfboards")
);

Read an item

Perform a point read operation by using both the unique identifier (id) and partition key fields. Use container.ReadItem to efficiently retrieve the specific item.

ItemResponse<Product> response = await container.ReadItemAsync<Product>(
    id: "aaaaaaaa-0000-1111-2222-bbbbbbbbbbbb",
    partitionKey: new PartitionKey("gear-surf-surfboards")
);

Query items

Perform a query over multiple items in a container using container.GetItemQueryIterator. Find all items within a specified category using this parameterized query:

SELECT * FROM products p WHERE p.category = @category

string query = "SELECT * FROM products p WHERE p.category = @category"

var query = new QueryDefinition(query)
  .WithParameter("@category", "gear-surf-surfboards");

using FeedIterator<Product> feed = container.GetItemQueryIterator<Product>(
    queryDefinition: query
);

Parse the paginated results of the query by looping through each page of results using feed.ReadNextAsync. Use feed.HasMoreResults to determine if there are any results left at the start of each loop.

List<Product> items = new();
while (feed.HasMoreResults)
{
    FeedResponse<Product> response = await feed.ReadNextAsync();
    foreach (Product item in response)
    {
        items.Add(item);
    }
}

Explore your data

Use the Visual Studio Code extension for Azure Cosmos DB to explore your NoSQL data. You can perform core database operations including, but not limited to:

Performing queries using a scrapbook or the query editor
Modifying, updating, creating, and deleting items
Importing bulk data from other sources
Managing databases and containers

For more information, see How-to use Visual Studio Code extension to explore Azure Cosmos DB for NoSQL data.

Clean up resources

When you no longer need the sample application or resources, remove the corresponding deployment and all resources.

azd down

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