@startuml
'https://plantuml.com/class-diagram

class Company{
-designation
}

class SNSSystem{
-Database
}

class Employee{
-id
-password
-salary
}

class Role

class Nurse

class Administrator

class CenterCoordinator

Company "1" -- SNSSystem : owns >
Company "1" -- "*" Employee : has >
SNSSystem "1" -- Employee : has >
Employee "*" -- "1" Role : has <
Role "1" -- "*" Nurse : is part of <
Role "1" -- "*" CenterCoordinator : is part of <
Role "1" -- "*" Administrator : manages <


@enduml