ER diagram and Schema for a simple game database. I am trying to figure out my foreign/unique keys for my database. I have identified the entities, attributes and primary keys. Any help is appreciated.

Game Database

Entity: player

Attribute: id_number (primary key), jersey_number, player_name, start_ability, coach_name

Entity: player_skills

Attribute: skill_id (primary key), skill_type, stats, years_experience, specialty

Entity: location

Attribute: location_id(primary key), location_name, year_team_located, climate, teams_per_location

Entity: coach

Attribute: coach_id(primary key), coach_name, coach_level, number_players, times_player_drafted