MongoDB quiz

Test your MongoDB knowledge with a free interactive quiz — 50 questions with answers and explanations. No signup needed to play.

What does a single-field index on `email` enable?

1. What does a single-field index on `email` enable?
2. Which is more accurate (but slower) on large collections: `countDocuments` or `estimatedDocumentCount`?
3. Which logical operator combines conditions so that ALL must match?
4. What is the difference between `updateOne` and `updateMany`?
5. In MongoDB terminology, what does a "collection" correspond to in a relational database?
6. If you insert a document without an `_id` field, what happens?
7. In `db.users.find({}, {name: 1, _id: 0})`, what does the second argument do?
8. Which method inserts multiple documents in a single call?
9. What does enabling schema validation with `$jsonSchema` give you?
10. Which combination paginates results?
11. What does `db.users.find({age: {$gt: 18}})` return?
12. What is BSON?

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