JPA @OneToMany 关系表没有足够的列
在我的应用程序中，我具有以下 @OneToMany 关系：
@Entity
public class ReservedLessons extends ReservedSessions implements Serializable {
@OneToMany(cascade={CascadeType.PERSIST})
private List<Lesson> reservedLessons;
}
@Entity
public class Lesson extends Sessions implements Serializable { ... }
我希望看到包含 2 列 ReservedLessons_ID 和 reservedLessons_ID 的表 reservedlessons_lesson。但是，当我运行该应用程序时，该表只有 1 列 ReservedLessons_ID。
在我的应用程序中，我还有其他几个 @OneToMany 关系，并且所有关系都有一个包含 2 列的表。如果您能告诉我我做错了什么，我将非常感激。
In my app, I have the following @OneToMany relationship:
@Entity
public class ReservedLessons extends ReservedSessions implements Serializable {
@OneToMany(cascade={CascadeType.PERSIST})
private List<Lesson> reservedLessons;
}
@Entity
public class Lesson extends Sessions implements Serializable { ... }
I expected to see the table reservedlessons_lesson with 2 columns ReservedLessons_ID and reservedLessons_ID. However, when I ran the app, the table only had 1 column ReservedLessons_ID.
In my app, I also have several other @OneToMany relationships and all of them have a table with 2 columns. I'd be very grateful if you could show me what I have done wrong.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（2）
您应该在映射的另一端使用 @ManyToOne 使其成为双向（示例)
You should use @ManyToOne at other side of your mapping to make it bidirectional (example)
我发现了问题。当我命名
ReservedLessons实体及其reservedLessons属性时，我很粗心。由于 MySQL 中的 2 个列名实际上是相同的，因此我的连接表缺少应有的列。将ReservedLessons更改为ReservedLesson后，我的联接表现在按预期具有 2 列ReservedLesson_ID和reservedLessons_ID。I found the problem. I was careless when I was naming my
ReservedLessonsentity and itsreservedLessonsproperty. Since the 2 column names are actually the same in MySQL, my join table lacks a column it should have. After I change myReservedLessonstoReservedLesson, my join table now has 2 columnsReservedLesson_IDandreservedLessons_IDas expected.