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我阅读了很多关于@OneToMany 的主题和论坛,但不幸的是,这些都无济于事。

例如,我们有这样的实体:

@Entity
@Table(name = "MANAGER")
public class Manager{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "MAN_ID")
    private long id;

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "MAN_ID", updatable=true)     
    private Set<Workers> workers;

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "MAN_ID", updatable=true)   
    private Set<Helpers> helpers;

...
}

@Entity
@Table(name = "WORKERS")
public class Workers{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "ID")
    private long id;

...
}

@Entity
@Table(name = "HELPERS")
public class Helpers{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "ID")
    private long id;

...
}

现在我试图保存第一次 Manager 对象(两个集合都不为空)

Session session = getSession();
Transaction tx = session.beginTransaction();
session.save(holder);
tx.commit();

作为回报,我看到 hibernate 如何尝试插入,但没有更新工人和助手。当我从 DB 取回 Manager 时,两个列表都是空的(null)。我在这里想念什么?

4

1 回答 1

2

看起来我错过了可为空的

@JoinColumn(name = "MAN_ID", nullable = false)  
于 2012-12-18T13:59:22.063 回答