MongoDB is a popular NoSQL document-oriented database that is widely used by developers and organizations for its scalability, flexibility, and high performance in handling large volumes of unstructured data.
As the demand for MongoDB experts grows, it is important for job seekers to prepare for MongoDB interviews by studying common interviewquestions and understanding the key concepts and features of MongoDB.
Get ready for MongoDB interviews questions and answers. This section covers key aspects like as : What Is MongoDB? or what is mongodb used for? or mongodb interview questions and answers or mongodb interview questions and answers ? or mongodb interview questions and answers for experienced or mongodb interview questions and answers for freshers or Top MongoDB Interview Questions and Answers.
1. What is MongoDB? (Most Imp Question)
MongoDB is an open-source, cross-platform, document-oriented, and non-relational database system. MongoDB is developed by MongoDB Inc. and was first released on February 11, 2009. Its stable release is MongoDB 5.0.5 released on 6 December 2021. It is written in different programming languages like JavaScript, Python, Java, PHP, C++, C, Ruby, Perl.
MongoDB is a NoSQL document-oriented database that stores data in JSON-like documents with dynamic schemas.
It is designed to handle large volumes of unstructured data.
2. What is the Features of MongoDB ? (Imp question)
The main features of MongoDB which make it unique are:
High Performance: Data operations on MongoDB are fast and easy because of their NoSQL nature. Data can be quickly stored, manipulated, and retrieved without any compromise on data integrity.
Scalability: In the Big Data era, MongoDB data can be distributed across a cluster of machines quickly and equally, free of bulkiness. The scalability of MongoDB handles a growing amount of data capably. Sharding is a process in MongoDB used to horizontally scale the data across multiple servers when the size of data increases.
Availability: Data is highly available with MongoDB as it makes multiple copies of the same data and sends copies of data across different servers. In case any server fails, data can be retrieved from another server without delay.
Flexibility: MongoDB can easily be combined with different Database Management Systems, both SQL and NoSQL types. Document-oriented structure makes MongoDB schema dynamically flexible and different types of data can be easily stored and manipulated.
3. What is Difference Between SQL(MongoDB) and NoSQL(MySQL) ? or Difference Between SQL and NoSQL Database? (Most Imp Question)
These are the Key Difference Between SQL(MongoDB) and NoSQL(MySQL):
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NoSQL (MongoDB, DynamoDb) |
SQL(MySQL, PostgreSQL etc) |
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NoSQL represents data as of JSON documents. |
SQL represents data in tables and rows. |
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In NoSQL, you don’t need to define the schema. |
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NoSQL doesn’t support JOIN. |
SQL supports JOIN operations. |
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while SQL uses the Structured Query Language(SQL). |
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NoSQL is an ideal choice if you have unstructured and/or structured data with the potential for rapid growt . |
SQL is agreat choice if you have structured data and need a traditional relational database. |
4. What is a document in MongoDB? (Imp Question)
A document is a set of key-value pairs stored in a BSON format in MongoDB. BSON is a binary representation of JSON.
5. What is a collection in MongoDB? (Imp Question)
A collection in MongoDB is a group of documents that share a similar structure. It is equivalent to a table in a relational database.
6. What is a replica set in MongoDB?
A replica set in MongoDB is a group of MongoDB servers that store the same data to provide redundancy and high availability.
7. What is sharding in MongoDB?
Sharding in MongoDB is a method of partitioning data across multiple servers to improve performance and scalability.
8. What is indexing in MongoDB?
Indexing in MongoDB is the process of creating an index on a field in a collection to improve query performance.
9. What are the different types of indexing in MongoDB?
MongoDB supports several types of indexing, including single field, compound, multi-key, text, and geospatial indexing.
10. What is MapReduce in MongoDB?
MapReduce is a data processing technique in MongoDB that involves mapping data to a set of key-value pairs, reducing the values based on the keys, and aggregating the results.
11. What is the aggregation pipeline in MongoDB?
The aggregation pipeline is a framework in MongoDB that allows for the processing of data through a series of stages, including
filtering, sorting, grouping, and transforming data extra.
12. What is the difference between update and save in MongoDB?
The update method in MongoDB modifies existing documents, while the save method either updates an existing document or inserts a new document if one does not already exist.
13. What is GridFS in MongoDB?
GridFS is a specification for storing and retrieving large files, such as images and videos, in MongoDB.If file size more than 16 MB.
14. What is the difference between a primary key and a secondary key intorials MongoDB?
A primary key in MongoDB is a unique identifier for a document, while a secondary key is used for indexing and querying data.
15. How does MongoDB ensure data consistency?
MongoDB uses a two-phase commit protocol to ensure data consistency in distributed environments.
16. How does MongoDB handle schema changes?
MongoDB allows for flexible schemas, and schema changes can be made without affecting existing data.
17. How does MongoDB handle transactions?
MongoDB supports multi-document transactions that allow for atomicity, consistency, isolation, and durability (ACID) properties.
18. What is the role of the mongod process in MongoDB?
The mongod process is the primary daemon process in MongoDB that manages data storage, indexing, and access.
19. What is the role of the mongo shell in MongoDB?
The mongo shell is a command-line interface that allows users to interact with MongoDB and perform administrative tasks.
20. How does MongoDB handle security?
MongoDB provides several security features, including authentication, authorization, encryption, and auditing.
21. What is the difference between a join and a lookup in MongoDB?
A join in MongoDB involves combining data from multiple collections, while a lookup involves retrieving related data from another collection.
22. How does MongoDB handle data backup and recovery?
MongoDB presents numerous backup and restoration options, together with warm backups, factor-in-time restoration, and incremental backups.
Conclusion:
MongoDB is a famous NoSQL report-orientated database that offers scalability, flexibility, and excessive performance for handling massive volumes of unstructured records.
Job seekers can prepare for MongoDB interviews by studying these questions and answers to gain a better understanding of MongoDB concepts/features and resolve these questions like as: What Is MongoDB? or what is mongodb used for? or mongodb interview questions and answers or mongodb interview questions and answers ? or mongodb interview questions and answers for experienced or mongodb interview questions and answers for freshers or Top MongoDB Interview Questions and Answers