MongoDB quiz

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

In `db.users.find({}, {name: 1, _id: 0})`, what does the second argument do?

1. In `db.users.find({}, {name: 1, _id: 0})`, what does the second argument do?
2. What does `db.users.find({age: {$gt: 18}})` return?
3. What does the `upsert` option do in an update?
4. How are dates typically stored in MongoDB?
5. Which update operator increments a numeric field?
6. What kind of database is MongoDB?
7. What is BSON?
8. Which is more accurate (but slower) on large collections: `countDocuments` or `estimatedDocumentCount`?
9. A MongoDB connection string typically starts with which prefix?
10. When deciding between embedding a sub-document and referencing it by id, the most common starting heuristic is:
11. What does enabling schema validation with `$jsonSchema` give you?
12. What is the difference between `updateOne` and `updateMany`?

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