Azure Cosmos DB is a globally distributed, multi-model database service provided by Microsoft Azure. It supports multiple data models, including document, key-value, graph, and column-family data models. In this article, we’ll explore how to add and retrieve data from Azure Cosmos DB using .NET Core, focusing on the document model.
Prerequisites
Before you begin, ensure you have the following:
- An Azure account with access to Cosmos DB.
- A Cosmos DB account and a database with a container.
Setting up the .NET Core project
1. Create a new .NET Core Console App:
Open a terminal and run the following commands:
dotnet new console -n CosmosDbExample
cd CosmosDbExamplebash
2. Install Azure Cosmos DB SDK:
Install the Azure Cosmos DB SDK for .NET by running the following command:
dotnet add package Microsoft.Azure.Cosmos
Writing code to add and retrieve data
Now, let’s write code to interact with Azure Cosmos DB.
Add data
using Microsoft.Azure.Cosmos;
using System;
using System.Threading.Tasks;
class Program
{
private const string EndpointUrl = "your_cosmos_db_endpoint";
private const string PrimaryKey = "your_cosmos_db_primary_key";
private const string DatabaseId = "YourDatabaseId";
private const string ContainerId = "YourContainerId";
static async Task Main(string[] args)
{
CosmosClient cosmosClient = new CosmosClient(EndpointUrl, PrimaryKey);
Database database = await cosmosClient.CreateDatabaseIfNotExistsAsync(DatabaseId);
Container container = await database.CreateContainerIfNotExistsAsync(ContainerId, "/PartitionKey");
// Add data
dynamic item = new
{
Id = Guid.NewGuid().ToString(),
Name = "John Snow",
Age = 30,
PartitionKey = "PartitionKeyValue"
};
ItemResponse<dynamic> response = await container.CreateItemAsync(item, new PartitionKey(item.PartitionKey));
Console.WriteLine($"Created item in database with id: {response.Resource.Id}");
}
}
Replace `”your_cosmos_db_endpoint”`, `”your_cosmos_db_primary_key”`, `”YourDatabaseId”`, and `”YourContainerId”` with your Cosmos DB account details.
Retrieve data
using Microsoft.Azure.Cosmos;
using System;
using System.Linq;
using System.Threading.Tasks;
class Program
{
private const string EndpointUrl = "your_cosmos_db_endpoint";
private const string PrimaryKey = "your_cosmos_db_primary_key";
private const string DatabaseId = "YourDatabaseId";
private const string ContainerId = "YourContainerId";
static async Task Main(string[] args)
{
CosmosClient cosmosClient = new CosmosClient(EndpointUrl, PrimaryKey);
Database database = cosmosClient.GetDatabase(DatabaseId);
Container container = database.GetContainer(ContainerId);
// Retrieve data
var query = new QueryDefinition("SELECT * FROM c WHERE c.Age > @age")
.WithParameter("@age", 25);
var iterator = container.GetItemQueryIterator<dynamic>(query);
while (iterator.HasMoreResults)
{
FeedResponse<dynamic> response = await iterator.ReadNextAsync();
foreach (var item in response)
{
Console.WriteLine($"Id: {item.Id}, Name: {item.Name}, Age: {item.Age}");
}
}
}
}
Replace the same placeholders as in the previous example.
Final thoughts
In this article, we’ve walked through the process of adding and retrieving data from Azure Cosmos DB using .NET Core. Azure Cosmos DB provides a flexible and scalable solution for managing diverse data types, and the .NET SDK simplifies the development process.
Remember to handle sensitive information, such as connection strings and keys, securely in a production environment. Additionally, consider error handling and logging to make your application more robust.
By following these steps, you should be able to integrate Azure Cosmos DB into your .NET Core applications, allowing you to store and retrieve data efficiently.