When MongoDB was initially released, in 2009, it took the database world by storm. At that point the vast majority of databases in use were relational, and MongoDB quickly grew to be the most popular non-relational database (also known as “NoSQL”.)
NoSQL databases difer from relational databases (such as MySQL, PostgreSQL, etc.) in that they model the data they store in ways other than tables related one to another.
MongoDB, specifically, is a “document-oriented database.” It saves data in “documents” encoded in BSON format (“Binary JSON”, a JSON ...