DP-420: Designing and Implementing Cloud-Native Applications Using Microsoft Azure Cosmos DBDemo

By Microsoft · Question Mode

QuestionQ184

Design and implement data models

You plan to create an Azure Cosmos DB database named db1 with two containers: one for blog posts and one for users. Each blog-post item will include:

  • A single blog post
  • All comments associated with that blog post
  • The names of the users who created the blog post and added the comments

You need to update usernames in the user container without causing data-integrity issues, while minimizing administrative and development effort.

What should the solution include?

Select
In the user container, implement:
In the blog post container, implement:
Explanation

Because usernames are denormalized into blog-post items, changing a username in the user container must propagate to every copy. You attach the change feed processor to the user container so it reacts to each username update, then, for each changed user, it invokes a stored procedure on the blog-post container to bulk-update all matching items within a logical partition transactionally - minimizing development and administrative effort. A post-trigger is wrong because triggers only fire on operations submitted to that container and are not invoked by a change in the user container. A user-defined function only computes values inside queries and cannot modify data.

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