Models

  erDiagram
    Comment }o--|| User : "written by"
    Unavailability }o--|| User : "reported by"
    Compensation ||--o{ Schedule : ""
    User ||--o{ ShiftOffer : ""
    User ||--o{ Shift : ""
    User ||--o{ Roster : schedules
    User |o--o{ ShiftUpdate : ""
    ShiftUpdate |o--o| Shift : ShiftOld1
    ShiftUpdate |o--o| Shift : ShiftOld2
    ShiftUpdate |o--o{ Shift : ShiftsNew
    Schedule ||--|{ ShiftOffer : ""
    ShiftOffer |o--o| Shift : "may result in"
    Schedule |o--|| Shift : ""
    Compensation |o--o{ Shift : ""
    Shift }|--|| Roster : "belongs to"
    Shift ||--|{ BillingShift : ""
    BillingShift }|--|| Billing : ""