Ultimate Mongodb Test - 78+ MCQs: MongoDB test: Assess Your Knowledge with MongoDB Questions and Answers

1. In MongoDB, how do you create a compound index?

db.createIndex({ field1: 1, field2: 1 })

db.index({ field1: 'asc', field2: 'desc' })

db.ensureIndex({ field1: 'ascending', field2: 'descending' })

db.field1.field2.createIndex()

2. What is the purpose of the `db.currentOp()` method in MongoDB?

To create a new operation

To retrieve information about current operations

To update an existing operation

To terminate an operation

3. How does MongoDB ensure high availability in a replica set?

Automated backups

Data partitioning

Data mirroring

Failover mechanism

4. What is the purpose of the `explain()` method in MongoDB?

To provide documentation for queries

To analyze and report on the query execution plan

To debug MongoDB server issues

To format query results

5. What is the purpose of the $push operator in MongoDB?

Array modification

Document deletion

Data encryption

Query optimization

6. In MongoDB, what is the primary role of the `mongos` process?

Client application for MongoDB

MongoDB database server

Query optimizer

Shard router in a sharded cluster

7. In MongoDB, what is the purpose of the `$nin` operator?

Matches values not in a specified array

Matches values in a specified array

Negates the results of an aggregation stage

Selects documents with a not-in condition

8. Which aggregation stage is used to group documents by a specific field?

$group

$sort

$match

$project

9. What is the purpose of the `db.killOp()` method in MongoDB?

To terminate a specific operation

To create a new operation

To update an existing operation

To retrieve information about current operations

10. What is the syntax for creating an ascending index on a field in MongoDB?

db.index({ field: 1 })

db.createIndex({ field: 'asc' })

db.ensureIndex({ field: 'ascending' })

db.field.createIndex()

11. What is the primary purpose of the MongoDB aggregation framework?

Data encryption

Data validation

Data modeling

Data transformation

12. Which authentication mechanism is commonly used in MongoDB?

OAuth

JWT

Kerberos

SCRAM-SHA-256

13. What is the purpose of the `db.createView()` method in MongoDB?

To create a new database

To create a new collection

To create a view on an existing collection

To create an index on a collection

14. What is the purpose of the $graphLookup stage in MongoDB aggregation?

Data modeling

Recursive queries

Data validation

Query optimization

15. Explain the concept of document-level locking in MongoDB.

Concurrency control

Data validation

Data modeling

Query optimization

16. What is sharding in MongoDB?

The process of encrypting data

The process of splitting data across multiple servers

The process of sorting documents in a collection

The process of updating MongoDB version

17. How can you update multiple documents in MongoDB?

db.modifyMany()

db.bulkUpdate()

db.updateMany()

db.editMultiple()

18. What is the purpose of the `$elemMatch` operator in MongoDB?

Matches arrays with a specific element

Matches arrays with all specified elements

Matches arrays without a specific element

Matches arrays based on position

19. Explain the purpose of the $lookup stage in the MongoDB aggregation pipeline.

Data enrichment

Data transformation

Data validation

Data modeling

20. In MongoDB, what is the primary purpose of the `oplog`?

To store binary data

To record all write operations

To optimize query performance

To manage database users

21. In MongoDB, what is the purpose of the `explain()` method?

To provide documentation for queries

To analyze and report on the query execution plan

To debug MongoDB server issues

To format query results

22. In MongoDB, how can you exclude a field from the query results?

db.exclude()

db.excludeField()

db.project()

db.hide()

23. What is the purpose of the `ttl` index type in MongoDB?

To store timestamps

To perform text search

To create a time-to-live index

To encrypt data

24. Which command is used to create a new database in MongoDB?

db.makeDatabase()

db.new()

db.createDatabase()

use <databaseName>

25. Which type of data format does MongoDB primarily store?

Tabular

JSON-like Documents

CSV

Binary

26. What is the primary purpose of MongoDB?

Relational Database Management

Document-Oriented Database Management

Graph Database Management

Key-Value Pair Database Management

27. What is the purpose of the `text` index type in MongoDB?

To store text data in a compressed format

To perform text search on string content

To encrypt text fields

To create a case-insensitive index

28. What is a covered query in MongoDB?

A query with optimal indexing

A query that retrieves only the indexed fields

A query with multiple conditions

A query that covers all documents in a collection

29. What is the `$all` operator used for in MongoDB?

Matches arrays with a specific element

Matches arrays with all specified elements

Negates the results of an aggregation stage

Selects documents with a not-in condition

30. Which operator is used for equality in MongoDB queries?

$eq

$equals

$eqs

$equal

31. Explain the significance of the ObjectId in MongoDB documents.

Primary key

Timestamp

Foreign key

Random identifier

32. Explain the difference between find() and findOne() methods in MongoDB.

Data aggregation

Data retrieval

Indexing strategy

Data validation

33. What is the default port for MongoDB?

27017

3306

8080

5432

34. How do you query documents in MongoDB to find those with a specific value in a field?

db.select()

db.find()

db.query()

db.search()

35. What is a sharded cluster in MongoDB, and why might it be used?

Replication mechanism

Distributed database

Security layer

Indexing strategy

36. How does MongoDB handle transactions, and what types of operations support transactions?

Concurrency control

Data validation

Data modeling

Atomic operations

37. What is the purpose of the TTL (Time To Live) index in MongoDB?

Document versioning

Automatic data expiration

Query optimization

Geospatial indexing

38. What is the purpose of the $redact stage in MongoDB aggregation?

Data transformation

Data security

Data validation

Query optimization

39. Explain the role of the oplog in MongoDB and its significance in replication.

Data transformation

Replication log

Data validation

Query optimization

40. What is the significance of the GridFS in MongoDB?

Data compression

Large file storage

Authentication

Query optimization

41. How can you perform a case-sensitive search in MongoDB?

$regex: /pattern/i

$caseSensitive: true

$matchCase: true

$cs: /pattern/

42. Explain the concept of MongoDB change streams and their use cases.

Data transformation

Real-time data updates

Data validation

Data modeling

43. What is the role of an index in MongoDB, and how does it impact query performance?

Data encryption

Data compression

Data validation

Query optimization

44. In MongoDB, what is a capped collection, and when might it be used?

Data modeling

Automatic data expiration

Fixed-size collection

Query optimization

45. In MongoDB, what does the `dbStats()` command provide?

Statistics about a specific collection

Statistics about a specific document

Statistics about the entire database

Statistics about index usage

46. In MongoDB, what is a replica set?

A set of related tables

A group of database servers

A collection of documents

A cluster of indexes

47. What is the purpose of the `$exists` operator in MongoDB?

To check if a document exists

To filter documents with a specified field

To determine if a field is empty

To validate the existence of an index

48. Explain the concept of readConcern in MongoDB and its impact on data consistency.

Concurrency control

Data validation

Read operations

Query optimization

49. In MongoDB, what is the role of the WiredTiger storage engine?

Query optimization

Concurrency control

Data compression

Authentication

50. In MongoDB, what is a capped collection?

A collection with a maximum size

A collection with predefined documents

A collection with nested documents

A collection with unlimited storage

MongoDB MCQ Test 1