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. What does `db.users.distinct("country")` return?
3. What does the MongoDB aggregation framework do?
4. Which is more accurate (but slower) on large collections: `countDocuments` or `estimatedDocumentCount`?
5. What does `db.users.find({age: {$gt: 18}})` return?
6. Which logical operator combines conditions so that ALL must match?
7. When deciding between embedding a sub-document and referencing it by id, the most common starting heuristic is:
8. How are dates typically stored in MongoDB?
9. What does enabling schema validation with `$jsonSchema` give you?
10. Which combination paginates results?
11. In MongoDB Compass (or `mongosh`), what is the easiest way to see how a query is executed?
12. In MongoDB terminology, what does a "collection" correspond to in a relational database?

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