@startuml
' Entities definition
entity "Genres" as genres {
    + genre_id: INTEGER [PK]
    --
    genre_name: TEXT [UNIQUE, NOT NULL]
}

entity "Movies" as movies {
    + movie_id: INTEGER [PK]
    --
    title: TEXT [NOT NULL]
    genre_id: INTEGER [FK]
    duration: INTEGER [CHECK > 0]
}

entity "Halls" as halls {
    + hall_id: INTEGER [PK]
    --
    hall_name: TEXT [NOT NULL, UNIQUE]
    capacity: INTEGER [CHECK > 0]
}

entity "Sessions" as sessions {
    + session_id: INTEGER [PK]
    --
    movie_id: INTEGER [FK]
    hall_id: INTEGER [FK]
    session_time: DATETIME [NOT NULL]
    ticket_price: REAL [CHECK >= 0]
}

entity "Tickets" as tickets {
    + ticket_id: INTEGER [PK]
    --
    session_id: INTEGER [FK]
    seat_number: INTEGER [CHECK > 0]
    sold_at: TIMESTAMP [DEFAULT CURRENT_TIMESTAMP]
}

' Relationships
genres ||--o{ movies : "1 to Many"
movies ||--o{ sessions : "1 to Many"
halls ||--o{ sessions : "1 to Many"
sessions ||--o{ tickets : "1 to Many"

@enduml