JPA和Hibernate中的@Id批注 [英] @Id annotation in JPA and Hibernate
问题描述
如果我不想自动生成主键,那么我想提供ID,并以表的第一列作为主键.
If I don't want to automatically generate the primary Key, instead, I want to supply the ID with the first column of the table as primary key.
2 A
4 B
7 D
13 E
...
我希望第一列2,4、7、13为表的主键.我应该只使用@Id做注释吗?
I want the first column 2,4, 7, 13 to be the primary key of the table. Should I just use @Id to do the annotation?
@Entity
public class Code {
@Id
@Column(unique=true)
private int id;
...
}
或者,如果使用@Id,在这种情况下,主键将始终自动生成,而不是使用第一列吗?
Or, if @Id is used, the primary key will be always automatically generated, instead of using the first column, in this case?
推荐答案
@Id
仅声明主键.它不会插入生成的值.如果使用@GeneratedValue
,它将生成该字段的值.
@Id
will only declare the primary key. it will not insert generated value. if you use @GeneratedValue
then it will generate the value of the field.
这篇关于JPA和Hibernate中的@Id批注的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!