休眠與更新子表一對多的關系

Question

我有兩個名為OwnerDetails和VehicleDetails pojo類，如下所示

@Entity
public class OwnerDetails implements Serializable{


    private static final long serialVersionUID = 1L;

    @Id
    @Column(name="Owner_id")
    private int id;
    @Column(name="owner_name")
    private String ownerName;
    @Column(name="email_id")
    private String email;
    @Column(name="mobile")
    private String mobile;
    @Column(name="land_line")
    private String phone;
    @Column(name="Mailing_Address")
    private String mailing_address;

    @OneToMany(mappedBy="ownerDetails", cascade=CascadeType.ALL)
    private Set<VehicleDetails> vehicleDetails;
    // getter & Setter...

}

@Entity
public class VehicleDetails implements Serializable{


    private static final long serialVersionUID = 1L;


    @Id
    private int v_id;
    @Column(name="TYPE")
    private String type;
    @Column(name="AC_OR_NON_AC")
    private boolean aircondition;
    @Column(name="SEATING_CAPACITY")
    private int seatingCapacity;
    @Column(name="FUEL_TYPE")
    private String fuel_type;
    @Column(name="Reg_number")
    private String reg_number;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="Owner_id")
    private OwnerDetails ownerDetails;
// getter & Setter....

}

而主程序是

public static void main(String[] args) throws InterruptedException {


        SessionFactory sf=getSessionFactory();
        Session session=sf.getCurrentSession();
        Transaction txn=session.beginTransaction();

        OwnerDetails own=(OwnerDetails)session.get(OwnerDetails.class, 1);

        Set<VehicleDetails> vhSet=new HashSet<VehicleDetails>();
        VehicleDetails vh=new VehicleDetails();
        vh.setAircondition(true);
        vh.setFuel_type("DIESEL");
        vh.setReg_number("TN32 AA 5555");
        vh.setSeatingCapacity(12);
        vh.setV_id(11);
        vh.setType("INNOVA");
        vh.setOwnerDetails(own);
        vhSet.add(vh);

        own.setVehicleDetails(vhSet);

         session.saveOrUpdate(own);
         txn.commit();

    }

成功保存所有者詳細信息和車輛詳細信息之后，我遇到的問題沒有任何問題。

但是我需要再添加一個具有相同所有者詳細信息的車輛詳細信息。 它將使用ownerid更新當前vihicledetails實例，並且vihicledetails中的現有行將使用null ownerid更新。

請找到下表。

Answer 1

看起來像語句own.setVehicleDetails(vhSet); 導致將VehicleDetails設置替換為新的。 而是使用own.getVehicleDetails().add(vh) 。 這會將新的vehicleDetails實體添加到與ownerDetails關聯的現有vehicleDetails集中，而不是替換它。