Question

我想使用JPArepository“保存”（如添加功能）更新表中的数据。添加它的工作，但更新不一样。

错误

java.sql.SQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`timesheetdb`.`app`, CONSTRAINT `app_ibfk_1` FOREIGN KEY (`batch_id`) REFERENCES `batch` (`batch_id`))

这是我的代码

App.java

@Entity
@Table(name = "app")
public class App {
@Id
@GeneratedValue
@Column(name="app_id" , nullable = true)
private int app_id;

@Column(name="app_no")
private String app_no; 

@ManyToOne(fetch = FetchType.LAZY ,cascade = {CascadeType.PERSIST,CascadeType.MERGE} )
@JoinColumn(name="batch_id" , referencedColumnName = "batch_id",insertable=false, updatable=false)
private Batch batch = new Batch() ;


//get and set

Batch.java

@Entity
@Table(name = "batch")
public class Batch {
@Id
@GeneratedValue
@Column(name="batch_id" , unique = true, nullable = false ,insertable= false , updatable = false) 
private int batch_id;


@Column(name="batch_name")
private String batch_name;

//get and set

休眠日志

Hibernate: insert into batch (batch_name, batch_id) values (?, ?)
Hibernate: insert into app (app_id,app_no, batch_id) values (?, ?,?)

问题

1。为什么不更新日志？

2。有时我测试是否看到错误，我看到了新的约束，例如FKsbmff76rtfh40rncf2110t4pf而不是app_id约束？

3。问题是因为我将多对一映射错了吗？

Answer 1

而不是

cascade = {CascadeType.PERSIST,CascadeType.MERGE}

尝试使用，

cascade = CascadeType.ALL

您可以参考链接https://vladmihalcea.com/a-beginners-guide-to-jpa-and-hibernate-cascade-types/以获得更好的理解。

还从下面一行中删除新的Batch（）

@ManyToOne(fetch = FetchType.LAZY ,cascade = {CascadeType.PERSIST,CascadeType.MERGE} )
@JoinColumn(name="batch_id" , referencedColumnName = "batch_id",insertable=false, updatable=false)
private Batch batch = new Batch() ;

JPA Hibernate无法添加或更新子行

1 个答案: