What is the exact point of using external database system if I have simple relations (95% querries are dependant on ID). I am storing users and their stats. Why would I use external database if I can have neat constructions like: db.users[32] = something Array of 500K users is not that big effort for RAM Pros are: no problematic asynchronity (instant results) easy export/import dealing with database like with a native object LITERALLY ps. and considerations: Would it be faster or slower to do collection[3] than db.query("select ... I am going to store it as a file/s There is only ONE application/process accessing this data, and the code is executed line by line - please don't elaborate about locking. Please don't answer with database propositions but why to use external DB over native array/object - I have experience in a few databases - that's not the case. What I am building is a client/gateway/server(s) game. Gateway deals with all users data, processing, authenticating, writing statistics e.t.c No other part of software needs to access directly to this data/database.