Hi, good day, Maybe I could help you. I have seen your ER entity, I think you need to relation display with tvchanel and not with player,
then you need a relationship between player and room. so ,
table display will be: (just an example)
display_id, room_id, tvchanel_id, is_enabled
relation between player and room depends of you project, generally it has to be a middle table
room_player
id_room_player, id_room, id_player
but if you assign a specifics rooms to users,
would be in talbe player a field with room
id_player, id_room
so,when you run a query to get list of chanel
first you have to go to room of user, then go to display, then tv chanel,
I hope you understant, if you have trouble run the query, let me know I can show you via teamviewer.
good luck.