Add data to calendar tool from user

Hi

im trying to add data to calendar tool , so the information i want to add is from the current user logged in database so i can display an event name and customer details to the calendar.

so what i did is to create a user, event infor, and customer info in separate database, and connected the 2 database to user database, now when i want to extract the event name from user database it doesn’t allow me.