我现在开始学习jpa，我有一个关于owner和非owner的概念的问题，根据我读到的一篇文章，non-owner将是每个没有mappdBy的属性，但是当存在双向关系时，没有mappdBy表示法，我不确定是否有一个关系的所有者，我还注意到mappdBy选项只在它是@OneTo多而不是@ManyToOne时出现，也就是说，什么真正定义了关系的所有者以及它在实践中如何影响

每次运行应用程序时加载的初始数据

sql

insert into client (id, name) values (null, 'Marina');
insert into client (id, name) values (null, 'Joana');

insert into demand(id, name) values(null, "Banana");
insert into demand(id, name) values(null, "Apple");
insert into demand(id, name) values(null, "jabuticaba");

Demand.java

@Getter
@Setter
@EqualsAndHashCode(onlyExplicitlyIncluded = true)
@Entity
@Table(name = "demand")
public class Demand {

    @Id
    @EqualsAndHashCode.Include
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @ManyToOne
    private Client client;

    private String name;
}

Client.java

@Getter
@Setter
@EqualsAndHashCode(onlyExplicitlyIncluded = true)
@Entity
@Table(name = "client")
public class Client {

    @EqualsAndHashCode.Include
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;

    @OneToMany
    private List<Demand> demand;
}

Main.java

public class Main {

public static void main(String[] args) {
    
     EntityManagerFactory entityManagerFactory = 
              Persistence.createEntityManagerFactory("unit");
    
     EntityManager entityManager = entityManagerFactory.createEntityManager();
     Client client = entityManager.find(Client.class, 1);
    
     Demand demand1 = entityManager.find(Demand.class, 1);
     Demand demand2 = entityManager.find(Demand.class, 2);
     Demand demand3 = entityManager.find(Demand.class, 3);
    
     entityManager.getTransaction().begin();
     client.setDemand(Arrays.asList(demand1, demand2, demand3));
     entityManager.getTransaction().commit();
    
     client = entityManager.find(Client.class, 1);
     System.out.println("Client name: " + client.getName() + " Demand name " + 
     client.getDemand().get(0).getName());
     System.out.println("Client name: " + client.getName() + " Demand name " + 
     client.getDemand().get(1).getName());
   }
}

我的最后一个问题是，谁是关系的所有者，因为我没有使用mappby？另一件事，我注意到它创建了一个中间表，当我不使用mappdBy时，如果有人能给我很多关于mappdBy如何工作的细节，我将非常感激。