MongoDB is a popular NoSQL database that is attracting a lot of developers worldwide. It is different from traditional relational databases such as MySQL, PostgreSQL, and SQLite3. The main big difference with MongoDB compared to other databases is it is schemaless and stores collections and documents. Think of MongoDB collections as tables, and documents as rows in SQL databases. However, in MongoDB, there is no relationship between collections. This schemaless design allows MongoDB to scale horizontally using a mechanism called Sharding. MongoDB stores data as BSON files on disk. BSON is an efficient binary format for operation and data transfer. Almost all MongoDB clients convert JSON into BSON and vice versa while inserting or retrieving documents.
Many big companies such as Expedia, Comcast, and MetLife built their applications on MongoDB. It has been...