Free MongoDB Associate-Data-Modeler Exam Questions

Question 1

In a MongoDB database for an online bookstore, you're designing a data model to handle books, authors, and reviews efficiently, considering a complex scenario involving relationships and potential data skew due to varying numbers of reviews per book. Given the requirements:

Each book can have multiple authors.

Each author can write multiple books.

Books can have a large number of reviews, but most have a few or none, creating potential data skew.

The application frequently queries books with their authors and a sample of reviews to avoid performance issues due to data skew.

How should you model the relationships among books, authors, and reviews to optimize for query performance and data management?

A : Embed authors and a fixed number of top reviews in each book document.

B : Use a separate collection for reviews and link them to books with a book ID. Authors and books are embedded within each other's documents.

C : Reference authors and reviews in the book document with foreign keys.

D : Embed books within author documents, including all reviews for each book.

Answer: A

Question 2

In designing a catalog application, a developer is dealing with Product entities that have multiple Review entities. The application frequently displays products along with the top three reviews based on ratings. How should the developer model this data to optimize for performance?

A : Use a separate collection to maintain a list of product IDs and their associated top three review IDs.

B : Embed the top three Review documents within each Product document.

C : Store each Review in a separate document, linking them to their respective Product via a product ID.

D : Embed all Review documents within their respective Product document.

Answer: B

Question 3

In designing a data model for a new online bookstore application, you are tasked with structuring the relationship between Books and Authors. Each book can have one or more authors, and each author can write multiple books. Considering the requirement for fast reads and updates of both books and their associated authors, which of the following data modeling patterns would be most optimal?

A : Embedding authors within books documents.

B : Storing all books and authors in a single document.

C : Referencing authors from books documents by storing author IDs in books.

D : Using a separate collection for each author's books.

Answer: A

Question 4

A mobile application tracks user activities, interactions, and engagement metrics to offer personalized content and recommendations. To optimize the application's performance, particularly for generating monthly engagement reports and user insights, a data modeler is tasked with designing an efficient data storage strategy. What approach should the data modeler adopt to best meet these requirements?

A : Maintain separate collections for users, activities, and interactions, calculating engagement metrics and insights in real time upon each query.

B : Use a single collection for activities and employ on-the-fly aggregation queries for generating user engagement reports and insights whenever needed.

C : Store all user data, including activities and interactions, as embedded documents within a single user document in a single collection.

D : Utilize separate collections for Users, Activities, and EngagementMetrics. Use the computed pattern to periodically update EngagementMetrics with aggregated data.

Answer: D

Question 5

In a MongoDB database, the events collection stores documents related to various events with fields like eventId, title, location, and date. The schema needs to be updated to support a new tags array field, which will store keywords related to each event. What is the most effective way to introduce this change, ensuring backward compatibility and minimal disruption to the existing application?

A : Create a separate collection named eventTags to store tags with references to their corresponding events by eventId, and adjust the application to aggregate data from both collections.

B : Introduce a schemaVersion field in the documents of the events collection, setting it to 2 for documents including the tags field, and modify the application to handle documents based on their schema version.

C : Add the tags field with an empty array as the default value to all existing documents in the events collection, requiring minimal application changes.

D : Migrate all documents to a new collection named events_v2, including the tags field for new documents, and update the application code to reference the new collection.

Answer: B