Runtime communication with database

Hi there, i am fairly new to unity and i cannot find the right way to solve my problem. Even Mr. google cant answer it for me (maybe i just give him the wrong keywords)

here is my problem: i want my unity project to communicate with a database (mysql preferred but i don't really care), while the game is running i want to change content according to database changes. These changes should also be possible from the same game but other instances of the game on another computer could have an impact for the current one. this all should work without security issues!

i appreciate every useful comment and links (where this problem might be already solved)

thx in advance TKOK