MangoDB Basic Interview Questions
  1. Why is MongoDB not chosen for a 32-bit system?
  2. In which format MongoDB represents document structure?
  3. Are null values permitted?
  4. On a high level, compare SQL databases and MongoDB.
  5. How does Scale-Out occur in MongoDB?
  6. Does MongoDB write to disk automatically or slowly?
  7. How to query MongoDB with %like%?
  8. How does MongoDB provide concurrency?
  9. “When you add more slaves to a replica set, both writes and reads become faster.” Is this claim correct or incorrect? Why is this so?
  10. What are the similarities and differences between sharding and replication in MongoDB?
  11. What is the difference between a secondary and a slave?
  12. What is the significance of a covered query?
  13. Define the Aggregation pipeline.
  14. When to use MongoDB?
  15. When to use - embeded or referenced relationship?
  16. Can you configure the cache size for WiredTiger?
  17. Define the application-level Encryption.
  18. What are 32-bit nuances?
  19. While creating Schema in MongoDB what are the points need to be taken in consideration?
  20. Does an update fsync to the disk immediately?
  21. What are some features of MongoDB?
  22. How can concurrency affect replica sets primary?
  23. Which are the two storage engines used by MongoDB?
  24. What will happen when you remove a document from database in MongoDB? Does MongoDB remove it from disk?
  25. Is it essential for MongoDB to have a ton of RAM?
  26. Is an object attribute deleted from the store as it is removed?
  27. Explain relationships in MongoDB?
  28. When do we use a namespace in MongoDB?
  29. How can applications access real-time data changes in MongoDB?
  30. How many indexes does MongoDB create by default for a new collection?
  31. Can you configure the cache size for MMAPv1?
  32. Define MapReduce.
  33. Describe oplog?
  34. Do the MongoDB databases have schema?
  35. Explain the situation when an index does not fit into RAM.
  36. Explain what is GridFS in MongoDB?
  37. What exactly do you mean by NoSQL databases? Is MongoDB a NoSQL database? Please elaborate.
  38. When and to what degree does data become multi-slice?
  39. Why use MongoDB?
  40. What will have to do if a shard is down or slow and you do a query?
  41. Why MongoDB is known as best NoSQL database?
  42. What type of data is stored by MongoDB?
  43. When should we embed one document within another in MongoDB?
  44. What are the data types in MongoDB?
  45. What are MongoDB’s data models?
  46. What is a Collection in MongoDB?
  47. In MongoDB, how are constraints managed?
  48. What is a Document in MongoDB?
  49. What is Splitting in MongoDB?
  50. What is sharding in MongoDB?
  51. What is the use of the dot notation in MongoDB?
  52. Why are MongoDB data files large in size?
  53. What is the use of the db command?
  54. Is MongoDB better than other SQL databases? If yes then how?
  55. Define Auditing.
  56. How does MongoDB do text search?
  57. Can journaling features be used to perform safe hot backups?
  58. What are the main distinctions between BSON documents in MongoDB and JSON documents in general?
  59. MongoDB is referred to as a schema-less database. Is this true? How can you make a schema in MongoDB?
  60. How does MongoDB handle transactions or locking?
  61. What is Vertical Scaling?
  62. What are Databases in MongoDB?
  63. In MongoDB, how can CRUD operations be performed?
  64. State the difference between find() and limit() method.
  65. To do safe backups what is the feature in MongoDB that you can use?
  66. What type of DBMS is MongoDB?
  67. Define Horizontal Scaling.
  68. Can one MongoDB operation lock more than one databases? If yes, how?
MangoDB Advanced Interview Questions
  1. What are MongoDB Charts?
  2. What are the aggregate functions of MongoDB?
  3. How do we find array elements with multiple criteria?
  4. What are the pros and cons of normalizing data in a MongoDB database?
  5. Should I normalize my data before storing it in MongoDB?
  6. What do you mean by Transactions?
  7. Explain the concept of pipeline in the MongoDB aggregation framework.
  8. How do we control the MongoDB Performance?
  9. What is a Replica Set in MongoDB?
  10. What is the difference between the $all operator and the $in operator?
  11. Explain the concept of pipeline in the MongoDB aggregation framework.
  12. What is the Aggregation Framework in MongoDB?
  13. How MongoDB supports ACID transactions and locking functionalities?
  14. Assume there is a collection named users that looks like the one below. How can you get all houses in the “Rabia” neighborhood? [ { "_id" : ObjectId("5d011c94ee66e13d34c7c388"), "userName" : "kevin", "email" : "[email protected]", "password" : "affdsg342", "houses" : [ { "name" : "Big Villa", "neighborhood" : "Zew Ine" }, { "name" : "Small Villa", "neighborhood" : "Rabia" } ] }, { "_id" : ObjectId("5d011c94ee66e13d34c7c387"), "userName" : "sherif", "email" : "[email protected]", "password" : "67834783ujk", "houses" : [ { "name" : "New Mansion", "neighborhood" : "Nasr City" }, { "name" : "Old Villa", "neighborhood" : "Rabia" } ] } ]
  15. How can we sort the user-defined function? For example, x and y are integers, and how do we calculate “x-y”?
  16. What is the difference between the save and insert commands in MongoDB, and when do they act similarly?
  17. When a “moveChunk” fails, is it required to clean up partly moved docs?
  18. Assume there is a document with nested arrays that looks like the one below. How can you insert a “room” that has the name “Room 44” and size of “50” for a particular “house” that belongs to this user? { "_id": "682263", "userName" : "sherif", "email": "[email protected]", "password": "67834783ujk", "houses": [ { "_id": "2178123", "name": "New Mansion", "rooms": [ { "name": "4th bedroom", "size": "12" }, { "name": "kitchen", "size": "100" } ] } ] }
  19. A staple feature of relational database systems is the JOIN clause. What is the equivalent in MongoDB, and does it have any known limitations?
  20. Explain the Replication Architecture in MongoDB?
  21. Could you catch how the two queries are different? dealers.find({ "$and": [ { "length": { "$gt": 2000 } }, { "cars.weight": { "$gte": 800 } } ] }); and dealers.find({ "length": { "$gt": 2000 }, "cars.weight": { "$gte": 800 } });
  22. When is the SET Modifier used in MongoDB?
  23. How does MongoDB ensure high availability?
  24. What are some utilities for backup and restore in MongoDB?