erDiagram
    User {
        String id PK
        String email
        String fullName
        Timestamp createdDate
    }
    Business {
        UUID id PK
        String userId FK
        String businessName
        Timestamp createdAt
    }
    Vendor {
        UUID id PK
        String userId FK
        String companyName
        Timestamp createdAt
    }
    Staff {
        UUID id PK
        String userId FK
        UUID hubId FK
        UUID ownerId FK
        String fullName
        Timestamp createdAt
    }
    Shift {
        UUID id PK
        UUID orderId FK
        UUID ownerId FK
        ShiftStatus status
        Timestamp createdAt
    }
    Order {
        UUID id PK
        UUID ownerId FK
        UUID hubId FK
        OrderStatus status
        Timestamp createdAt
    }
    Position {
        UUID id PK
        UUID orderId FK
        UUID roleId FK
        UUID ownerId FK
        Timestamp createdAt
    }
    Task {
        UUID id PK
        UUID ownerId FK
        TaskStatus status
        Timestamp createdAt
    }
    Team {
        UUID id PK
        String ownerId FK
        String teamName
        Timestamp createdAt
    }
    TeamMember {
        UUID id PK
        UUID teamId FK
        UUID hubId FK
        String memberName
        Timestamp createdAt
    }
    Hub {
        UUID id PK
        UUID ownerId FK
        String name
        Timestamp createdAt
    }
    Account {
        UUID id PK
        UUID ownerId FK "polymorphic ownerId"
        String bank
        Timestamp createdAt
    }
    Document {
        UUID id PK
        UUID staffId FK
        DocumentStatus status
        Timestamp createdAt
    }
    Certificate {
        UUID id PK
        UUID staffId FK
        CertificateStatus status
        Timestamp createdAt
    }
    Contact {
        UUID id PK
        UUID staffId FK
        String name
        Timestamp createdAt
    }
    BenefitsData {
        UUID id PK
        UUID staffId FK
        String title
        Timestamp createdAt
    }
    Course {
        UUID id PK
        String title
        Timestamp createdAt
    }
    TaxForm {
        UUID id PK
        UUID staffId FK
        TaxFormStatus status
        Timestamp createdAt
    }
    TimeSheet {
        UUID id PK
        UUID staffId FK
        UUID shiftId FK
        TimeSheetStatus status
        Timestamp createdAt
    }
    Invoice {
        UUID id PK
        UUID ownerId FK
        InvoiceStatus status
        Timestamp createdAt
    }
    Assignment {
        UUID id PK
        UUID staffId FK
        UUID ownerId FK
        AssignmentStatus status
        Timestamp createdAt
    }
    Conversation {
        UUID id PK
        String subject
        Timestamp createdAt
    }
    Message {
        UUID id PK
        UUID conversationId FK
        String senderId
        Timestamp createdAt
    }
    Role {
        UUID id PK
        UUID ownerId FK
        String name
        Timestamp createdAt
    }
    RecentPayment {
        UUID id PK
        UUID payedUserId FK
        UUID ownerId FK
        RecentPaymentStatus status
        Timestamp createdAt
    }
    RequiredDoc {
        UUID id PK
        UUID ownerId FK
        ReqDocumentStatus status
        Timestamp createdAt
    }
    VendorRate {
        UUID id PK
        UUID vendorId FK
        String roleName
        Timestamp createdAt
    }
    Schedule {
        UUID id PK
        UUID positionId FK
        Timestamp createdAt
    }
    TaskComment {
        UUID id PK
        UUID taskId FK
        String authorName
        Timestamp createdAt
    }
    TeamHub {
        UUID id PK
        UUID teamId FK
        String hubName
        Timestamp createdAt
    }
    Application {
        UUID id PK
        UUID shiftId FK
        UUID staffId FK
        ApplicationStatus status
        Timestamp createdAt
    }
    StaffShift {
        UUID id PK
        UUID staffId FK
        UUID shiftId FK
        Timestamp createdAt
    }
    MemberTask {
        UUID id PK
        UUID teamMemberId FK
        UUID taskId FK
        Timestamp createdAt
    }
    StaffCourse {
        UUID id PK
        UUID staffId FK
        UUID courseId FK
        Timestamp createdAt
    }

    User ||--|{ Staff : "has profile"
    User ||--|{ Vendor : "can be"
    User ||--|{ Business : "can be"
    User ||--o{ ActivityLog : "generates"

    Business ||--o{ "Order" : "creates"
    Business ||--o{ Invoice : "receives"
    Business ||--o{ Task : "owns"
    Business ||--o{ Hub : "owns"
    Business ||--o{ Role : "defines"
    Business ||--o{ Shift : "posts"
    Business ||--o{ Staff : "employs"
    Business ||--o{ Account : "owns"
    
    Vendor ||--o{ VendorRate : "defines"
    Vendor ||--o{ Task : "owns"
    Vendor ||--o{ Hub : "owns"
    Vendor ||--o{ Role : "defines"
    Vendor ||--o{ Shift : "posts"
    Vendor ||--o{ Staff : "employs"
    Vendor ||--o{ Account : "owns"

    Staff ||--o{ Document : "has"
    Staff ||--o{ Certificate : "holds"
    Staff ||--o{ Contact : "has emergency"
    Staff ||--o{ BenefitsData : "accrues"
    Staff ||--o{ TaxForm : "submits"
    Staff ||--o{ TimeSheet : "fills"
    Staff ||--o{ Assignment : "receives"
    Staff ||--o{ Account : "owns"
    Staff ||--o{ RecentPayment : "is paid to"
    Staff ||--o{ RequiredDoc : "owns"
    Staff ||--o{ Application : "submits"
    Hub ||--o{ Staff : "is based at"
    
    Shift ||--o{ TimeSheet : "generates"
    Shift ||--o{ Application : "receives"
    
    "Order" ||--o{ Shift : "contains"
    "Order" ||--o{ Position : "requires"

    Task ||--o{ TaskComment : "has"

    Team ||--o{ TeamMember : "has"
    Team ||--o{ TeamHub : "operates in"
    
    Conversation ||--o{ Message : "contains"
    
    Position ||--o{ Schedule : "has"
    Role ||--o{ Position : "is for"

    %% Join Tables
    Staff ||--|{ StaffShift : "works"
    Shift ||--|{ StaffShift : "is worked by"
    Staff ||--|{ StaffCourse : "enrolls in"
    Course ||--|{ StaffCourse : "is taken by"
    TeamMember ||--|{ MemberTask : "assigned to"
    Task ||--|{ MemberTask : "is assigned to"