Hbernate:unideirection@oneToone具有级联启用

Question

我在航班（父）和航空公司（子）之间有一个单向的一对一映射，下面是我的代码-

public class Airline {
..
    @OneToOne(cascade=CascadeType.ALL)
    Flight flight;
}

航班没有任何航空公司的引用，这有id，命名他们的getter和setter。

    Flight flight= new Flight();
    flight.setName("flight2");

    Airline airline= new Airline();
    airline.setName("Air India");
    airline.setFlight(flight);

    Session session=sessionFactory.openSession();
    session.saveOrUpdate(airline);
    session.saveOrUpdate(flight);

public class Airline {
        @JoinColumn("flight_ref_id")
        @OneToOne(cascade=CascadeType.ALL)
        Flight flight;
    }


public class Flight {
        @OneToOne(cascade=CascadeType.ALL)
        Airline airline;
    }

    airline.setFlight(flight);
    flight.setAirLine(airline)
    Session session=sessionFactory.openSession();
    session.saveOrUpdate(airline);

mysql> select * from Airline;
+----+-----------+---------------+
| id | name      | flight_ref_id |
+----+-----------+---------------+
|  1 | Air India |          NULL |
+----+-----------+---------------+
1 row in set (0.00 sec)

mysql> select * from Flight;
+----+--------+------------+
| id | name   | airline_id |
+----+--------+------------+
|  1 | Del-NJ |          1 |
+----+--------+------------+

在dbflight_ref_id是null。为什么？

Answer 1

您需要添加@JoinColumn注释以添加多个用作飞行外键的列

public class Airline {
..
    @OneToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "flights_id", nullable = false)
    Flight flight;
}