mysql - 从哪里检索列表？

Question

例如，我有 2 个实体:客户、预订。一对多的双向关系。一位客户对多位预订，其中预订是所有者。当我想获得一位客户的所有预订时，我该怎么做？也许通过查询并从对象中使用 client.getReservations() 找到客户端？或者可以进行查询以查找 id 所在的预订。

客户端类:

ublic class Client extends Person {

    @OneToMany(mappedBy = "client", cascade = CascadeType.ALL, orphanRemoval = true)
    private List<Reservation> reservations = new ArrayList<>();

    public Client() {

    }

    public Client(String fullName, String phoneNumber, String email, String address) {

        super(fullName, phoneNumber, email, address);
    }

    public List<Reservation> getReservations() {
        return reservations;
    }

    public void addReservation(Reservation reservation) {
        this.reservations.add(reservation);
        reservation.setClient(this);
    }

    public void removeReservation(Reservation reservation) {
        this.getReservations().remove(reservation);
        reservation.setClient(null);

    }

预订舱位:

public class Reservation {

    // --- attributs ---
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "reservation_id")
    private Integer id;

    @Column(name = "created_on")
    @Temporal(TemporalType.DATE)
    @CreationTimestamp
    private Date createdOn;

    @Temporal(TemporalType.DATE)
    @Column(name = "last_updated")
    @UpdateTimestamp
    private Date lastUpdated;

    @Temporal(TemporalType.DATE)
    @Column(name = "date_to_supply")
    private Date dateToSupply;

    @Column(name = "total_sum")
    private double totalSum;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "client_id")
    private Client client;

Answer 1

在一对多关系中，当您在示例中加载客户端时，它将加载带有所有预留的客户端。如前所述 client.getReservations()。将获得该特定客户的所有预订。