One of my projects is to automate a LEGO City, especially the train section. For that i need a place to save all the information. Initially choose a SQL database (MySQL), but as necessary to create custom tables for each case and create relations. But as i didn’t know what information was supplied by the City and i would need a communication protocol ( i’ll use MQTT. In the future i’ll write a tutorial how to use it) i choose a NoSQl database, MongoDB.