Implement a point operation that creates, updates, and deletes documents

Microsoft Azure Cosmos DB is a globally distributed database service that provides high availability and scalability with comprehensive SLAs. It supports multiple data models, including document, key-value, column-family, graph, and time-series data. In this article, we will focus on the document data model and explore how to implement a point operation that creates, updates, and deletes documents related to an exam.

Prerequisites

Before we dive into the implementation details, make sure you have the following prerequisites in place:

1. An Azure subscription: You will need an Azure subscription to create and manage resources in Azure.
2. Azure Cosmos DB account: Create an Azure Cosmos DB account in the Azure portal. Select the “SQL API” option when creating the account as we will be using the SQL API to interact with the data.
3. Programming environment: Choose a programming language and framework of your choice that supports Azure Cosmos DB. This article assumes you will be using C# and the .NET framework.

Creating the Document Database

To begin, let’s create a document database to store our exam-related data. Follow the steps below:

1. Navigate to the Azure portal (portal.azure.com) and sign in with your Azure account.
2. Click on “Create a Resource” and search for “Azure Cosmos DB”.
3. Click on “Azure Cosmos DB” and then click “Create”.
4. Provide a unique ID for your Azure Cosmos DB account, select the desired API (SQL API), and choose the appropriate subscription and resource group.
5. Specify the geographic location where you want your data to be stored.
6. Under the “Settings” tab, select “Enable multi-region writes” if you want to enable writes from multiple regions.
7. Click “Review + Create” and then click “Create” to create the Azure Cosmos DB account.

Once the Cosmos DB account is created, we can proceed with implementing the point operations for creating, updating, and deleting exam-related documents.

Creating a Document

To create a document in Azure Cosmos DB, we need to establish a connection and use the appropriate client SDK. In this example, we will be using the .NET SDK. Here’s a sample code snippet to create an exam document:

using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Newtonsoft.Json;
using System;

In the above code snippet, we define a CosmosDBHelper class that handles the document creation. We create an instance of the DocumentClient class using the Cosmos DB account endpoint URL and primary key. In the CreateExamAsync method, we use the document client to create a document by passing the database and collection URIs along with the exam object.

Updating a Document

To update a document in Azure Cosmos DB, we need to retrieve the document, make the necessary changes, and then replace the document in the database. Here’s a sample code snippet to update an exam document:

public class CosmosDBHelper
{
// ...

In the above code snippet, the UpdateExamAsync method retrieves the existing document by its ID. We then update the desired properties of the document and replace it in the database using the ReplaceDocumentAsync method.

Deleting a Document

Deleting a document is straightforward. We only need to provide the document ID and the document’s self-link to delete it from the database. Here’s a sample code snippet to delete an exam document:

public class CosmosDBHelper
{
// ...

CosmosDBHelper.DeleteExamAsync(examId).GetAwaiter().GetResult();
}
}

In the above code snippet, the DeleteExamAsync method retrieves the existing document by its ID and then deletes it using the DeleteDocumentAsync method.

Conclusion

In this article, we explored how to implement point operations that create, update, and delete exam-related documents using Microsoft Azure Cosmos DB. We leveraged the .NET SDK to interact with the database and demonstrated sample code for each operation. Azure Cosmos DB provides an excellent platform for building scalable, globally distributed applications, and the document data model makes it easy to work with complex data structures.

Remember to explore the Azure Cosmos DB documentation for more in-depth information and to adapt the code samples to fit your specific requirements. Happy coding!