MongoDB Interview Questions and Answers, MongoDB Interview Questions and Answers Freshers, MongoDB Interview Questions and Answers, MongoDB Interview Questions

Before getting on to the MongoDB interview questions, the student must know that the MongoDB is a continuously varying field which needs the students as well as professionals to upgrade their skills with the new features and knowledge, to get fit for the jobs associated with MongoDB. This post related to MongoDB Interview Questions and Answers, MongoDB Interview Questions and Answers Freshers, MongoDB Interview Questions and Answers, MongoDB Interview Questions will help you let out find all the solutions that are frequently asked in you upcoming MongoDB interview.

Over thousands of vacancies available for the MongoDB developers, experts must be acquaintance with all the component of MongoDB technologies. This is necessary for the students in order to have in-depth knowledge of the subject so that they can have best employment opportunities in the future. Knowing every little detail about MongoDB is the best approach to solve the problems linked with problem.

APTRON has spent hours and hours in researching about the MongoDB Interview Questions and Answers, MongoDB Interview Questions and Answers Freshers, MongoDB Interview Questions and Answers, MongoDB Interview Questions that you might encounter in your upcoming interview.  All these questions will alone help you to crack the interview and make you the best among all your competitors.

First of all, let us tell you about how the MongoDB technology is evolving in today’s world and how demanding it is in the upcoming years. In fact, according to one study, most of the companies and businesses have moved to the MongoDB. Now, you cannot predict how huge the future is going to be for the people experienced in the related technologies.

Hence, if you are looking for boosting up your profile and securing your future, MongoDB will help you in reaching the zenith of your career. Apart from this, you would also have a lot of opportunities as a fresher.

These questions alone are omnipotent. Read and re-read the questions and their solutions to get accustomed to what you will be asked in the interview. These MongoDB interview questions and answers will also help you on your way to mastering the skills and will take you to the giant world where worldwide and local businesses, huge or medium, are picking up the best and quality MongoDB professionals.

This ultimate list of best MongoDB interview questions will ride you through the quick knowledge of the subject and topics like Mongo Shell, Using Eval, External Editor Integration, Saving Data, Set Operator. This MongoDB interview questions and answers can be your next gateway to your next job as a MongoDB expert.

These are very Basic MongoDB Interview Questions and Answers for freshers and experienced both.

Q1: Explain what is MongoDB?
A1: Mongo-DB is a document database which provides high performance, high availability and easy scalability.

Q2: What is “Namespace” in MongoDB?
A2: MongoDB stores BSON (Binary Interchange and Structure Object Notation) objects in the collection. The concatenation of the collection name and database name is called a namespace.

Q3: How can you see the connection used by Mongos?
A3: To see the connection used by Mongos use db_adminCommand (“connPoolStats”);

Q4: Explain what is a replica set?
A4: A replica set is a group of mongo instances that host the same data set. In replica set, one node is primary, and another is secondary. From primary to the secondary node all data replicates.

Q5: Explain what is the role of profiler in MongoDB?
A5: MongoDB database profiler shows performance characteristics of each operation against the database. You can find queries using the profiler that are slower than they should be.

Q6: Explain can you move old files in the moveChunk directory?
A6: Yes, it is possible to move old files in the moveChunk directory, during normal shard balancing operations these files are made as backups and can be deleted once the operations are done.

Q7: Mention what is Objecld composed of?
A7: Objectld is composed of

  • Timestamp
  • Client machine ID
  • Client process ID
  • 3 byte incremented counter

Q8: Mention what is the command syntax for inserting a document?
A8: For inserting a document command syntax is database.collection.insert (document).

Q9: Which all languages can be used with MongoDB?
A9: Currently, MonggoDB provides official driver support for C, C++, C#, Java, Node.js, Perl, PHP, Python, Ruby, Scala, Go and Erlang. MongoDB can easily be used with any of these languages. There are some other community supported drivers too but the above mentioned ones are officially provided by MongoDB.

Q10: Compare MongoDB and CouchDB at high level.
A10: Although both of these databases are document oriented, MongoDB is a better choice for applications which need dynamic queries and good performance on a very big database. On the other side, CouchDB is better used for applications with occasionally changing queries and pre-defined queries.

Q11: Does MongoDB support foreign key constraints?
A11: No. MongoDB does not support such relationships.

Q12: MongoDB uses BSON to represent document structures. True or False?
A12: True

Q13: If you remove a document from database, does MongoDB remove it from disk?
A13: Yes. Removing a document from database removes it from disk too.

Q14: How many indexes does MongoDB create by default for a new collection?
A14: By default, MongoDB created the _id collection for every collection.

Q15: What do you understand by NoSQL databases? Is MongoDB a NoSQL database? explain.
A15: At the present time, the internet is loaded with big data, big users, big complexity etc. and also becoming more complex day by day. NoSQL is answer of all these problems, It is not a traditional database management system, not even a relational database management system (RDBMS). NoSQL stands for “Not Only SQL”. NoSQL is a type of database that can handle and sort all type of unstructured, messy and complicated data. It is just a new way to think about the database.

Yes. MongoDB is a NoSQL database

Q16: What is the difference between MongoDB and MySQL?
A16: Although MongoDB and MySQL both are free and open source databases, there is a lot of difference between them in the term of data representation, relationship, transaction, querying data, schema design and definition, performance speed, normalization and many more. To compare MySQL with MongoDB is like a comparison between Relational and Non-relational databases.

Q17: Does MongoDB need a lot of RAM?
A17: No. There is no need a lot of RAM to run MongoDB. It can be run even on a small amount of RAM because it dynamically allocates and de-allocates RAM according to the requirement of the processes.

Q18: By default, which index is created by MongoDB for every collection?
A18: By default, the_id collection is created for every collection by MongoDB.

Q19: Why does Profiler use in MongoDB?
A19: MongoDB uses a database profiler to perform characteristics of each operation against the database. You can use a profiler to find queries and write operations

Q20: Why 32 bit version of MongoDB are not preferred ?
A20: Because MongoDB uses memory mapped files so when you run a 32-bit build of MongoDB, the total storage size of server is 2 GB. But when you run a 64-bit build of MongoDB, this provides virtually unlimited storage size. So 64-bit is preferred over 32-bit.

Q21: Can You Create An Index On An Array Field In Mongodb? If Yes, What Happens In This Case?
A21: Yes. An array field can be indexed in MongoDB. In this case, MongoDB would index each value of the array.

Q22: Explain The Structure Of Objectid In Mongodb.?
A22: ObjectID is a 12-byte BSON type with:

  • 4 bytes value representing seconds
  • 3 byte machine identifier
  • 2 byte process id
  • 3 byte counter

Q23: In MongoDB how do you use $set to update a nested value?
A23: Using the dot notation:
db.people.update({ }, { $set: { “address.street”: “Main Street” } })

Q24: Compare MongoDB and Cassandra

Criteria MongoDB Cassandra
Data Model Document Big Table like
Database scalability Read Write
Querying of data Multi-indexed Using Key or Scan

Q25: How to do transactions/locking in MongoDB?
A25: MongoDB does not use conventional locking with reduction, as it is planned to be light, high-speed and knowable in its presentation. It can be considered as parallel to the MySQL MyISAM auto entrust sculpt. With simplest business sustain, performance is enhanced, particularly in a structure with numerous servers.

Q26: When do we use Namespace in MongoDB?
A26: During sequencing of the names of the database and collection name Namespace is used.

Q27: How does MongoDB provide consistency?
A27: MongoDB uses the reader-writer locks, allowing simultaneous readers to access any supply like a database or any collection. But always offers private access to singles writes.

Q28: How does Journaling work in MongoDB?
A28: Write operations are saved in the memory while journaling is going on. The on-disk journal files are really dependable for the reason that the journal writes are habitual. Inside dbPath, a journal subdirectory is designed by MongoDB.

Q29: Explain replica set.
A29: It is a group of mongo instances that maintain same data set. Replica sets provide redundancy and high availability, and are the basis for all production deployments.

Q30: What is CRUD?
A30: Mongodb provides CRUD operations that are create, Read, Update, Delete.

Q31: What is use of GridFS in mongodb?
A31: GridFS is used for storing and retrieving the large files like audio, Images, Video files.

Q32: What is storage encryption?
A32: Storage Encryption encrypts all MongoDB data on the storage or operating system to ensure that only authorized processes can access protected data.

MongoDB Conclusion Interview FAQs

We know the list of MongoDB Interview Questions and Answers, MongoDB Interview Questions and Answers Freshers, MongoDB Interview Questions and Answers, MongoDB Interview Questions is overwhelming but the advantages of reading all the questions will maximize your potential and help you crack the interview. The surprising fact is that this MongoDB interview questions and answers post covers all the basic of the MongoDB technology and you have to check out the FAQs of different components of MongoDB too.

However, you will be asked with the questions in the interview related to the above mentioned questions. Preparing and understanding all the concept of MongoDB technology will help you strengthen the other little information around the topic.

After preparing these interview questions, we recommend you to go for a mock interview before facing the real one. You can take the help of your friend or a MongoDB expert to find the loop holes in your skills and knowledge. Moreover, this will also allow you in practicing and improving the communication skill which plays a vital role in getting placed and grabbing high salaries.

Remember, in the interview, the company or the business or you can say the examiner often checks your basic knowledge of the subject. If your basics is covered and strengthened, you can have the job of your dream. The industry experts understand that if the foundation of the student is already made up, it is easy for the company to educate the employ towards advance skills. If there are no basics, there is no meaning of having learnt the subject.

Therefore, it’s never too late to edge all the basics of any technology. If you think that you’ve not acquired the enough skills, you can join our upcoming batch of MongoDB Training in Noida. We are one of the best institute for MongoDB in noida which provide advance learning in the field of MongoDB Course. We’ve highly qualified professionals working with us and promise top quality education to the students.

We hope that you enjoyed reading MongoDB Interview Questions and Answers, MongoDB Interview Questions and Answers Freshers, MongoDB Interview Questions and Answers, MongoDB Interview Questions and all the FAQs associated with the interview. Do not forget to revise all the MongoDB interview questions and answers before going for the MongoDB interview. In addition to this, if you’ve any doubt or query associated with MongoDB, you can contact us anytime. We will be happy to help you out at our earliest convenience. At last, we wish you all the best for your upcoming interview on MongoDB Technology.