MCQs on MongoDB Basics | MongoDB MCQs
MongoDB is a modern NoSQL database designed for scalability, flexibility, and high performance. It uses a document-oriented model, storing data in BSON format, a binary representation of JSON. Developers prefer MongoDB for its powerful query language and seamless CRUD (Create, Read, Update, Delete) operations. Explore its fundamental concepts and gain valuable insights into databases, collections, documents, and query fundamentals with these MCQs.
MongoDB Basics
Q1. What does MongoDB primarily use to store data?
a) Tables
b) Documents
c) Rows
d) Columns
Q2. MongoDB is categorized as which type of database?
a) Relational
b) NoSQL
c) Columnar
d) Hierarchical
Q3. Which of the following best describes MongoDB?
a) Schema-less database
b) Table-based database
c) Fixed-schema database
d) XML-based database
Q4. What is the default port for MongoDB?
a) 8080
b) 27017
c) 3306
d) 1433
Q5. What command is used to check the MongoDB version?
a) show version;
b) db.version();
c) version();
d) mongo --version;
Understanding BSON and JSON
Q6. BSON is a binary representation of:
a) HTML
b) JSON
c) XML
d) YAML
Q7. Which is NOT a valid data type in BSON?
a) ObjectId
b) Decimal
c) Table
d) Binary Data
Q8. What is a key advantage of BSON over JSON?
a) Human-readability
b) Binary storage of data
c) Less data compression
d) Complex syntax
Q9. BSON adds support for which of the following?
a) Extended data types
b) Only integers
c) Nested tables
d) XML parsing
Q10. What is the main purpose of ObjectId in BSON?
a) To store strings
b) Unique identification for documents
c) Reference collections
d) Optimize queries
Databases, Collections, and Documents
Q11. In MongoDB, a collection is analogous to:
a) A column in SQL
b) A row in SQL
c) A table in SQL
d) A database in SQL
Q12. What is the primary role of a database in MongoDB?
a) Storing tables
b) Organizing collections
c) Storing BSON files
d) Managing columns
Q13. A single document in MongoDB is represented as:
a) Array
b) Dictionary-like structure
c) Table
d) Column
Q14. Which command is used to create a new collection?
a) db.createCollection()
b) create collection
c) db.addCollection()
d) create()
Q15. What happens if you insert a document into a collection that doesn’t exist?
a) It throws an error
b) The collection is automatically created
c) The document is rejected
d) Requires explicit permission
CRUD Operations: Insert, Read, Update, Delete
Q16. Which command is used to insert a document in MongoDB?
a) db.insert()
b) db.collection.insertOne()
c) insert()
d) collection.add()
Q17. How do you retrieve all documents in a collection?
a) db.collection.findAll()
b) db.collection.getAll()
c) db.collection.find()
d) findAll()
Q18. To update a single field in a document, you use:
a) $modify
b) $set
c) $update
d) $change
Q19. Which operator is used to delete all documents in a collection?
a) $deleteAll
b) remove()
c) deleteMany({})
d) $dropAll
Q20. What happens when you use deleteMany({}) on a collection?
a) Deletes all documents in the collection
b) Deletes specific documents based on criteria
c) Throws an error
d) Drops the collection
Query Language Fundamentals
Q21. Which method is used to filter documents based on conditions?
a) db.collection.filter()
b) db.collection.find()
c) db.filter()
d) findByCondition()
Q22. To retrieve only specific fields in MongoDB, use:
a) $select
b) db.collection.find({fields})
c) Projection
d) $includeFields
Q23. Which operator is used for AND conditions in MongoDB queries?
a) $and
b) $all
c) $both
d) $combine
Q24. How do you match documents where a field is greater than a value?
a) $gt
b) $gte
c) $greater
d) $greaterThan
Q25. Which operator checks if a field exists in a document?
a) $exists
b) $hasField
c) $fieldExists
d) $contains
Q26. MongoDB supports which type of indexes?
a) Single-field
b) Compound
c) Text
d) All of the above
Q27. Which function drops an index in MongoDB?
a) drop()
b) db.collection.dropIndex()
c) removeIndex()
d) db.collection.remove()
Q28. What does the $in operator do in a query?
a) Matches values equal to one of several specified values
b) Checks if a field exists
c) Matches fields that are not null
d) Filters documents with nested fields
Q29. Which query returns all documents where the “status” field equals “active”?
a) find({status: "active"})
b) db.find("status = active")
c) db.collection.find({status: "active"})
d) db.query({status: "active"})
Q30. Which command is used to sort documents in a query result?
a) db.collection.sortBy()
b) sort({field: order})
c) db.collection.find().sort()
d) orderBy()
Answer Key
| QNo | Answer |
|---|---|
| 1 | b) Documents |
| 2 | b) NoSQL |
| 3 | a) Schema-less database |
| 4 | b) 27017 |
| 5 | b) db.version(); |
| 6 | b) JSON |
| 7 | c) Table |
| 8 | b) Binary storage of data |
| 9 | a) Extended data types |
| 10 | b) Unique identification for documents |
| 11 | c) A table in SQL |
| 12 | b) Organizing collections |
| 13 | b) Dictionary-like structure |
| 14 | a) db.createCollection() |
| 15 | b) The collection is automatically created |
| 16 | b) db.collection.insertOne() |
| 17 | c) db.collection.find() |
| 18 | b) $set |
| 19 | c) deleteMany({}) |
| 20 | a) Deletes all documents in the collection |
| 21 | b) db.collection.find() |
| 22 | c) Projection |
| 23 | a) $and |
| 24 | a) $gt |
| 25 | a) $exists |
| 26 | d) All of the above |
| 27 | b) db.collection.dropIndex() |
| 28 | a) Matches values equal to one of several specified values |
| 29 | c) db.collection.find({status: "active"}) |
| 30 | c) db.collection.find().sort() |