and amenities such as swimming pool, convention center, restaurant, etc. Each hotel has a specific number of rooms which have a room number, number of beds and room type $($can be standard, suite, etc.$)$; rooms can also have ocean view. The company has many employees identified by their SN and have a name, date of birth and base salary. Each employee works for exactly one hotel, and each hotel must have at least one employee. Some employees are managers. Managers also have over pay $($salary above their base salary$).$ Managers are in charge of managing hotels $($starting from a specific date$),$ each manager manages exactly one hotel, and each hotel has exactly one manager. Some employees are janitors. Janitors are assigned to maintain rooms clean. Each room is assigned to exactly one janitor, but one janitormight clean one or more rooms