MongoDB Interview Questions and Answers
Question - 61 : - What is the use of the save() method?
Answer - 61 : - The save() method is used to replace the existing document with a new document.
Question - 62 : - What is MongoDB?
Answer - 62 : - MongoDB (from humongous) is a cross-platform document-oriented database. Classified as a NoSQL database, MongoDB eschews the traditional table-based relational database structure in favor of JSON-like documents with dynamic schemas (MongoDB calls the format ‘BSON’), making the integration of data in certain types of applications easier and faster. Released under a combination of the GNU Affero General Public License and the Apache License, MongoDB is open-source.
MongoDB was first developed by the software company 10gen (now, MongoDB Inc.) in October 2007 as a component of a planned platform as a service product. Then, the company shifted to an open-source development model in 2009, with 10gen offering commercial support and other services. Since then, MongoDB has been adopted as backend software by a number of major websites and services, including Craigslist, eBay, Foursquare, SourceForge, Viacom, and the New York Times, among others. Currently, MongoDB is the most popular NoSQL database system.
Question - 63 : - What is the use of MongoDB?
Answer - 63 : - MongoDB is a relational database management system (RDBMS) replacement for web applications. So, when we have something close to RDBMS, MongoDB could be of good use.
It gives us the additional partition tolerance, which RDMBS doesn’t offer, but it has problems with availability. Nonetheless, if we want more scalability, MongoDB would be the right choice for us. It’s suitable for real-time analytics and high-speed logging, and it’s highly scalable as well. Craigslist uses MongoDB for archived posts.
Question - 64 : - What do you understand by NoSQL databases? Is MongoDB a NoSQL database? Explain.
Answer - 64 : - Presently, the Internet is loaded with big data, big users, and so on that are becoming more complex day by day. NoSQL is the answer to 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’, and it is a type of database that can handle and sort all types of unstructured, messy, and complicated data. It is just a new way to think about databases.
Question - 65 : - What type of a DBMS is MongoDB?
Answer - 65 : - MongoDB is a document-oriented DBMS.
Question - 66 : - What is the difference between MongoDB and MySQL?
Answer - 66 : - Although both MongoDB and MySQL are free and open-source databases, there is a lot of difference between them in terms of data representation, relationships, 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.
Question - 67 : - What kind of a database is MongoDB?
Answer - 67 : - MongoDB is a document-oriented DBMS. We can think of it as MySQL but with JSON-like objects comprising the data model, rather than RDBMS tables. Significantly, MongoDB supports neither joins nor transactions. However, it features secondary indexes, an expressive query language, atomic writes on a per-document level, and fully-consistent reads. Operationally, MongoDB offers the master–slave replication with automated failover and built-in horizontal scaling via automated range-based partitioning.
Question - 68 : - Which language is MongoDB written in?
Answer - 68 : - MongoDB is implemented in C++. However, drivers and client libraries are typically written in their own respective languages. Although, some drivers use C extensions for better performance.
Question - 69 : - What are the limitations of the 32-bit versions of MongoDB?
Answer - 69 : - MongoDB uses memory-mapped files. When running a 32-bit build of MongoDB, the total storage size for the server, including data and indexes, is 2 GB. For this reason, we do not deploy MongoDB to production on 32-bit machines.
If we’re running a 64-bit build of MongoDB, there’s virtually no limit to the storage size. For production deployments, 64-bit builds and operating systems are strongly recommended.
Question - 70 : - While creating a schema in MongoDB, what are the points need to be taken into consideration?
Answer - 70 : - While creating a schema in MongoDB, the points need to be taken care of are as follows:
1. Design our schema according to the user requirements
2. Combine objects into one document if we want to use them together; otherwise, separate them
3. Do joins while on write, and not when it is on read
4. For most frequent use cases, optimize the schema
5. Do complex aggregation in the schema