Top 15 frequently asked MongoDB interview questions and answers are as follows:
1.What is MongoDB?
MongoDB is a cross-platform document-oriented database. Classified as a NoSQL database, MongoDB uses JSON like documents with dynamic schemas (MongoDB calls the format BSON), making the integration of data in certain types of applications easier and faster. It is published under a combination of GNU Affero General Public License and the Apache License, MongoDB is free and open-source software.
2. What are the key features of MongoDB?
There are 3 main features of Mongodb that are
- automatic scaling
- High performance
- High availability.
3.What type of DBMS is MongoDB?
MongoDB is a document oriented DBMS.
4.What do you understand by NoSQL databases?Is MongoDB a NoSQL Database?Explain?
These days, the internet is loaded with big data, big users and big complexity etc. and also becoming more complex day by day. NoSQL is the solution 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 which can handle and sort all types of messy, complicated and unstructured data. It’s a new way to think about the database. Yes. MongoDB is a NoSQL database.
5.Judge against MongoDB with Couchbase and CouchbaseDB?
Although Mongo DB with Couchbase and Couchbase DB are common in many ways, but still they are different in the case of necessities for execution of the model, duplications, crossing points, storage, etc.
6.When do we use Namespace in MongoDB?
During sequencing of the names of the database and collection name Namespace is used.
7.How can we move the old file in moveChunk Directory?
Once the functions are done, the old files are converted to backup files and moved to the moveChunk directory at the time of balancing the slices.
8.If you remove an Object attribute, is it deleted from database?
Yes, it is deleted. So better eliminate the attribute and then save the object again.
9.How does MongoDB provides consistency?
MongoDB uses the reader-writer locks that allow simultaneous readers to access any supply like a database /any collection. But always provides private access to single writes.
10.What is Aggregation in MongoDB?
Aggregations are operations which process data records and return computed results.
11.What is CRUD?
Mongodb provides CRUD operations that are Create, Read, Update, and Delete.
12.What is Sharding?
Sharding means to store the data on the multiple machines.
13.Which type of data MongoDB store?
MongoDB stores data in the form of documents, which are JSON-like field and value pairs.
14.Which language is used to write MongoDB?
C++ language is used for writing and implementing mongodb.
15.Define MongoDB Projection?
Projection is used to select only necessary data. It will not select whole data of a document.