英文:
How to create Spring Entity and Repository without primary key
问题
以下是翻译好的部分：
我有一张包含两列 user_id 和 role_id 的表。表中没有唯一的列，也无法添加唯一列。在没有主键的情况下，我如何在Spring中创建Entity和Repository？
这是我的 UserRole.class：
public class UserRole {
@Column(name = "user_id")
private int userId;
@Column(name = "role_id")
private int roleId;
//getters and setters
}
但是，使用这个类会出现以下错误：
嵌套异常为 org.hibernate.AnnotationException: 未为实体指定标识符：
我看到其中一个解决方法是将所有列用作标识符，但我不知道如何实现。
英文:
I have a table with two columns user_id and role_id. There's no unique column in table and I can't add one. How can I create Entity and Repository in Spring without a primary key?
This is my UserRole.class
public class UserRole {
@Column(name = "user_id")
private int userId;
@Column(name = "role_id")
private int roleId;
//getters and setters
}
But with this class i get the following error:
> nested exception is org.hibernate.AnnotationException: No identifier specified for entity:
I saw that one of the answers is to use all of the columns as the id, but i have no idea how to do it.
答案1
得分: 1
请参考此帖子中的答案。这应该能帮助您。
另一个选项是，如果这是一个关联表，那么您可以创建嵌入式PK。
@Embeddable
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder(toBuilder = true)
public class PersonGroupPK implements Serializable {
//default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;
@Column(insertable=false,unique = false, updatable=false, nullable=false)
private Long personId;
@Column(insertable=false, unique = false,updatable=false, nullable=false)
private Long groupId;
}
英文:
Please see the awnser in this post. This should help you.
Another Option is if this is a join table, than you could make Embeded PK
@Embeddable
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder(toBuilder = true)
public class PersonGroupPK implements Serializable {
//default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;
@Column(insertable=false,unique = false, updatable=false, nullable=false)
private Long personId;
@Column(insertable=false, unique = false,updatable=false, nullable=false)
private Long groupId;
}
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