MongoDB

MongoDB is an open source, document-oriented, and cross-platform database. It is primarily written in C++. It is also the leading NoSQL database and tied with the SQL database in fifth position after PostgreSQL. It provides high performance, high availability, and easy scalability. MongoDB uses JSON-like documents with schema. MongoDB, developed by MongoDB Inc., is free to use. It is published under a combination of the GNU Affero General Public License and the Apache License.

Let's go through the MongoDB features:

• Rich query support: We can query the database as we do with SQL databases. It has a large query set that supports insert, update, delete and select operations. MongoDB supports fields, range queries, and regular expressions. Queries also support the projection where they return a value for specific keys.
• Indexing: MongoDB supports primary and secondary indices in its fields.
• Replication: Replication means providing more than one copy of data. MongoDB provides multiple copies of data with multiple servers. It provides fault tolerance, if one database server goes down, the application uses other database servers.
• Load balancing: Replica sets provide multiple copies of data. MongoDB can scale read operation by client request directly to the secondary node. This divides loads across multiple servers.
• File storage: We can store documents up to 6 MB directly to the MongoDB JSON field. For documents exceeding the size limit of 16 MB, MongoDB provides GridFS to store in chunks.
• Aggregation: The aggregate function takes a number of records and calculates single results like sum, min, and max. MongoDB provides a data pipeline and multistage pipeline to move large data to the aggregate function which improves performance.