How to write a query to find which seats are booked and which are not - spring

Question

I am using Spring JPA
I have 3 entities
1- Event
2- Seat
3- Reservation
Event has one to many relation with Seat and Reservation
Reservation has a one to many relation with Seat
(Event will have the seats created after its creation and then it will be assigned to the particular event)
(When users make reservations, each reservation can have multiple seats for the particular event)
What I've done so far:
The Event class
#Entity
#Data
#NoArgsConstructor #AllArgsConstructor
public class Event {
#Id
#GeneratedValue(strategy = AUTO)
private Long id;
#OneToMany(mappedBy = "event", fetch = FetchType.LAZY)
private List<Seat> seats;
#OneToMany(mappedBy = "event", fetch = FetchType.LAZY)
private List<Reservation> reservations;
}
The Seat class
#Entity
#Data
#AllArgsConstructor
#NoArgsConstructor
public class Seat {
#Id
#GeneratedValue(strategy = AUTO)
private Long id;
private String seatCode;
#ManyToOne(fetch = FetchType.LAZY)
#JoinTable(name = "event_seats")
private Event event;
#ManyToOne
#JoinTable(name = "seat_reservation")
private Reservation reservation;
}
The Reservation class
#Entity
#Data
#AllArgsConstructor
#NoArgsConstructor
public class Reservation {
#Id
#GeneratedValue(strategy = AUTO)
private Long id;
#ManyToOne
private User user;
#ManyToOne(fetch = FetchType.LAZY)
#JoinTable(name = "event_reservations")
private Event event;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "reservation")
private Collection<Seat> seats;
}
**Is the tables and relations design correct?
When I create a reservation and add seats to it, the linking table (reservation_seats) doesn't get updated.
And how to write a query to determine which Event seats are booked and which are not?**

Answer 1

There is more than one way to do this using JPA depending of your knowledge.
Options Like Native Query, JPQL or JPA Criteria.
The native query would be like this:
With reservation:
SELECT * FROM seat s WHERE s.id IN (SELECT seat_id FROM seat_reservation)
With no reservation:
SELECT * FROM seat s WHERE s.id NOT IN (SELECT seat_id FROM seat_reservation)
There may be other ways to do this, but I think it's enough.