MongoDB and MySQL architectures

When I installed database management systems for the first time, I was confused about the server and workbench. I did not know why I had to install two things for the same "app" which was different from the normal apps we were using as clients. 

Actually it is decided by the architecture of the database management systems. Normally they are server-client architecture. The server is installed with an embedded command line client. But if you want an GUI client, such as MySQL workbench and Navicat, you have to install it seperatedly.

You can connect to the localhost or a remote server. Port number is needed when connecting to a server. 

Multiple clients can connect the same server; One Clients can connect to multiple servers (Distributed Systems?)

MySQL

MongoDB has the same story. The "app" you downloaded from the MongoDB official website and installed actually is MongoDB server(mongod.exe) with a commandline client. If you want a GUI client, you can Install Robo 3T. 

MongoDB