Quickstart: Azure Cosmos DB for Table library for .NET

Article
11/22/2024

APPLIES TO: Table

This quickstart shows how to get started with the Azure Cosmos DB for Table from a .NET application. The Azure Cosmos DB for Table is a schemaless data store allowing applications to store structured table data in the cloud. You learn how to create tables, rows, and perform basic tasks within your Azure Cosmos DB resource using the Azure SDK for .NET

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

Prerequisites

An Azure account with an active subscription. Create an account.
Azure Developer CLI
Docker Desktop
.NET 9.0

Initialize the project

Use the Azure Developer CLI (azd) to create an Azure Cosmos DB for Table 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-table-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.

Install the client library

The client library is available through NuGet, as the Azure.Data.Tables package.

Open a terminal and navigate to the /src/web folder.
```
cd ./src/web
```
If not already installed, install the Azure.Data.Tables package using dotnet add package.
```
dotnet add package Azure.Data.Tables
```
Open and review the src/web/Microsoft.Samples.Cosmos.Table.Quickstart.Web.csproj file to validate that the Azure.Data.Tables entry exists.

Object model

Name	Description
Azure.Data.Tables.TableServiceClient	This class is the primary client class and is used to manage account-wide metadata or databases.
Azure.Data.Tables.TableClient	This class represents the client for a table within the account.

The sample code in the template uses a table named cosmicworks-products. The cosmicworks-products table contains details such as name, category, quantity, price, a unique identifier, and a sale flag for each product. The container uses a unique identifier* as the row key and category as a partition key.

Authenticate the client

This sample creates a new instance of the TableServiceClient class.

TableServiceClient serviceClient = new(
    endpoint: new Uri("<azure-cosmos-db-table-account-endpoint>"),
    credential
);

Get a table

This sample creates an instance of the TableClient class using the GetTableClient method of the TableServiceClient class.

TableClient client = serviceClient.GetTableClient(
    tableName: "<azure-cosmos-db-table-name>"
);

Create an item

The easiest way to create a new item in a table is to create a class that implements the ITableEntity interface. You can then add your own properties to the class to populate columns of data in that table row.

public record Product : ITableEntity
{
    public string RowKey { get; set; } = $"{Guid.NewGuid()}";

    public string PartitionKey { get; set; } = String.Empty;

    public string Name { get; set; } = String.Empty;

    public int Quantity { get; set; } = 0;

    public decimal Price { get; set; } = 0.0m;

    public bool Clearance { get; set; } = false;

    public ETag ETag { get; set; } = ETag.All;

    public DateTimeOffset? Timestamp { get; set; }
};

Create an item in the collection using the Product class by calling TableClient.AddEntityAsync<T>.

Product entity = new()
{
    RowKey = "68719518391",
    PartitionKey = "gear-surf-surfboards",
    Name = "Surfboard",
    Quantity = 10,
    Price = 300.00m,
    Clearance = true
};

Response response = await client.UpsertEntityAsync<Product>(
    entity: entity,
    mode: TableUpdateMode.Replace
);

Get an item

You can retrieve a specific item from a table using the TableClient.GetEntityAsync<T> method. Provide the partitionKey and rowKey as parameters to identify the correct row to perform a quick point read of that item.

Response<Product> response = await client.GetEntityAsync<Product>(
    rowKey: "68719518391",
    partitionKey: "gear-surf-surfboards"
);

Query items

After you insert an item, you can also run a query to get all items that match a specific filter by using the TableClient.Query<T> method. This example filters products by category using Linq syntax, which is a benefit of using typed ITableEntity models like the Product class.

Note

You can also query items using OData syntax. You can see an example of this approach in the Query Data tutorial.

string category = "gear-surf-surfboards";

AsyncPageable<Product> results = client.QueryAsync<Product>(
    product => product.PartitionKey == category
);

Parse the paginated results of the query by looping through each page of results using asynchronous loop.

List<Product> entities = new();
await foreach (Product product in results)
{
    entities.Add(product);
}

Clean up resources

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

azd down