In this article, we will discuss the top 20 MongoDB interview questions and answers help job seekers prepare for their MongoDB interviews.
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 interview questions and understanding the key concepts and features of MongoDB.
1. What is MongoDB?
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 a document in MongoDB?
A document is a set of key-value pairs stored in a BSON format in MongoDB. BSON is a binary representation of JSON.
3. What is a collection in MongoDB?
A collection in MongoDB is a group of documents that share a similar structure. It is equivalent to a table in a relational database.
4. 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.
5. What is sharding in MongoDB?
Sharding in MongoDB is a method of partitioning data across multiple servers to improve performance and scalability.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
11. What is GridFS in MongoDB?
GridFS is a specification for storing and retrieving large files, such as images and videos, in MongoDB.
12. What is the difference between a primary key and a secondary key in MongoDB?
A primary key in MongoDB is a unique identifier for a document, while a secondary key is used for indexing and querying data.
13. How does MongoDB ensure data consistency?
MongoDB uses a two-phase commit protocol to ensure data consistency in distributed environments.
14. How does MongoDB handle schema changes?
MongoDB allows for flexible schemas, and schema changes can be made without affecting existing data.
15. How does MongoDB handle transactions?
MongoDB supports multi-document transactions that allow for atomicity, consistency, isolation, and durability (ACID) properties.
16. 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.
17. 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.
18. How does MongoDB handle security?
MongoDB provides several security features, including authentication, authorization, encryption, and auditing.
19. 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.
20. How does MongoDB handle data backup and recovery?
MongoDB provides several backup and recovery options, including hot backups, point-in-time recovery, and incremental backups.
In conclusion, MongoDB is a popular NoSQL document-oriented database that provides scalability, flexibility, and high performance for handling large volumes of unstructured data.
Job seekers can prepare for MongoDB interviews by studying these questions and answers to gain a better understanding of MongoDB concepts and features.
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