Server Commands
MongoDB is a database server that has clients that connect to the server over the network. The database server manages the database, while clients are used by applications or users to query data from the database. If you're wondering whether there are only databases (without a server), then yes, there are. For example, Microsoft Access is an example of a relational database without a database server. The main advantage of the client-server architecture is that the server consolidates control data management, user security, and concurrency for parallel access.
There is also a separation of physical and logical structures. The database server manages the database's physical structures, such as storage and memory. On the other hand, database clients usually have access only to logical database structures, such as collections, indexes, and views.
This section will briefly explain the physical and logical structures in MongoDB 4.4.