Technologies Coding Problems Bookmarks Learning Paths

Technologies Coding Problems Bookmarks Learning Paths

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Questions

8 of 12

1What are databases in mongoDB?

2What is MongoDB? List main features.

3List advantages and disadvantages of NosSQL and RDBMS.

4What is the difference between MongoDB Server and MongoDB Database?

5How does MongoDB ensures high availability?

6What is the BSON format?

7What is a collection in NoSQL database?

8What is a dcoument in NoSQL database?

9When to use RDBMS and when to use NoSQL DB in your applications?

10How is the json that we submit to mongoDB is converted to bson?

11How to connect to mongoDB database using in node js?

12Discuss what is NOSQL?

MongoDB

Bulk Operations

08 / 12

What is a dcoument in NoSQL database?

Difficulty: 4/10

document structure, schema flexibility, storage limits

A document in MongoDB is equivalent to a row in a table in RDBMS. Documents are stored in BSON format and are gathered together in collections.

1
It is a data structure composed of field and value pairs. MongoDB documents are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents.
2
Documents correspond to native data types in many programming languages.
3
Embedded documents and arrays reduce need for expensive joins.

Scenario Questions

0-2 years experience

1We need to store a user profile with name, email, and a list of addresses. How would you model that as a MongoDB document and what would the JSON look like?
2What happens if you try to insert a document that exceeds MongoDB's 16 MB BSON size limit?
3How would you write a query to return only the 'email' field from every document in the users collection?

Follow-up Questions

Can you walk me through a concrete example where you chose embed versus reference?
What are the practical limits you keep in mind when designing a document schema?
How would you monitor the impact of your document design on query latency?

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2-5 years experience

1A query on the orders collection is doing a full collection scan even though there's an index on customerId. Explain why the index might be ignored because of document design and how you'd fix it.
2During a feature rollout, some existing documents are missing a newly added 'status' field, causing the app to crash. How would you debug and remediate this without downtime?
3You need to add a new field to millions of existing documents. What strategies would you use to roll out the change safely in MongoDB?

5-8 years experience

1Design a sharding strategy for a high‑traffic events collection where each document can be several megabytes. Discuss how document size and schema affect shard‑key choice and balancing.
2Your service is suffering because documents contain very large embedded arrays. How would you refactor the schema, and what trade‑offs does moving to a referencing model introduce?
3Explain how the document model influences backup and restore times at petabyte scale, and what design choices can mitigate the impact.

8+ years experience

1We're migrating a legacy relational system to MongoDB. How would you decide which tables become single documents versus multiple related collections, considering future query patterns and data growth?
2Multiple teams store audit logs as documents with varying schemas. How would you establish a governance model to ensure consistency, queryability, and compliance over time?
3If we need multi‑tenant isolation while sharing the same MongoDB cluster, how would you structure documents and collections to balance security, performance, and operational overhead?

What is a dcoument in NoSQL database? | Basics | MongoDB Interview Questions | NextRound.in