How to use the MongoDB MCQ Quiz
- 1. Choose the length10 random MongoDB questions, or all 26.
- 2. AnswerTap an option. You see straight away whether it's right, with a one-line reason.
- 3. ReviewFinish to get your score and a list of every question with the correct answer.
What the quiz covers
The 26 questions are grouped into eight areas, shown above each question:
- Basics: BSON, collections, the _id field, ObjectId and the 16 MB document limit.
- Queries: comparison operators like
$gt,$in, projections, countDocuments and sorting. - Updates:
$set,$inc,$push,$unsetand upserts. - Aggregation:
$match,$group,$lookup,$unwindand why stage order matters. - Indexes: when they help, compound index prefixes and reading explain() output.
- Architecture, data modelling and Mongoose: replica sets, sharding, embedding versus referencing, and schemas.
A sample question explained
One question asks which query a compound index on { city: 1, age: 1 } helps most. The answer is find({ city: 'Noida', age: { $gt: 20 } }). A compound index is sorted by city first, then by age within each city, so it serves queries that use its leading fields. A query on age alone would still have to scan the whole index. The same idea, the "index prefix", applies to SQL databases too, which is why interviewers like it.
The quiz picks questions and option order at random, so a retake is a fresh test. Untick shuffle for a fixed order while you revise. Your score breaks down by area at the end, which shows you what to study next. For practice writing queries, try the SQL to MongoDB converter with queries you already know.
Frequently asked questions
Which MongoDB version do the questions follow?
Current MongoDB 6 and 7 behaviour. Deprecated methods like count() are mentioned as deprecated.
Are these real interview questions?
They are written by Uncodemy to cover topics commonly asked of MERN and back-end freshers. They are not copied from any company's test.
How many times can I take it?
As many as you like. Each attempt shuffles the questions.
Is the MongoDB MCQ quiz free to take?
Yes. The MongoDB MCQ quiz lets you answer every question with no form. At your first score screen we ask for your name and WhatsApp number once; after that, the MongoDB MCQ quiz and all other Uncodemy tools stay open.