Book Image

Guide to NoSQL with Azure Cosmos DB

By : Gaston C. Hillar, Daron Yöndem
Book Image

Guide to NoSQL with Azure Cosmos DB

By: Gaston C. Hillar, Daron Yöndem

Overview of this book

Cosmos DB is a NoSQL database service included in Azure that is continuously adding new features and has quickly become one of the most innovative services found in Azure, targeting mission-critical applications at a global scale. This book starts off by showing you the main features of Cosmos DB, their supported NoSQL data models and the foundations of its scalable and distributed architecture. You will learn to work with the latest available tools that simplify your tasks with Cosmos DB and reduce development costs, such as the Data Explorer in the Azure portal, Microsoft Azure Storage Explorer, and the Cosmos DB Emulator. Next, move on to working with databases and document collections. We will use the tools to run schema agnostic queries against collections with the Cosmos DB SQL dialect and understand their results. Then, we will create a first version of an application that uses the latest .NET Core SDK to interact with Cosmos DB. Next, we will create a second version of the application that will take advantage of important features that the combination of C# and the .NET Core SDK provides, such as POCOs and LINQ queries. By the end of the book, you will be able to build an application that works with a Cosmos DB NoSQL document database with C#, the .NET Core SDK, LINQ, and JSON.
Table of Contents (13 chapters)
Title Page
Packt Upsell

Understanding automatically generated key-value pairs

Scroll down to the latest lines of the document in the web-based editor and you will see new key-value pairs that were not part of the original document. The following screenshot shows the last lines in the embedded JSON editor:

The following lines show an example of the new key-value pairs. Note that many values will be different in your case:

    "_rid": "prUNAKtPjRoFAAAAAAAAAA==", 
    "_self": "dbs/prUNAA==/colls/prUNAKtPjRo=/docs/prUNAKtPjRoFAAAAAAAAAA==/", 
    "_etag": "\"22007fea-0000-0000-0000-5b86dbd60000\"", 
    "_attachments": "attachments/", 
    "_ts": 1535564758 

Cosmos DB added the following keys to our document, which start with an underscore (_) as a prefix and contain system-generated values for the document resource:

  • _rid: This string defines the resource ID; that is, a unique identifier for the resource. Cosmos DB uses this resource ID internally to identify and navigate through the document resource.
  • _self: This string...