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[英]Why is hibernate loading an entity again before doing saveAndFlush?
[英]When I do saveAndFlush on an entity object, I see hibernate generates 2 update queries. Why is it and how to avoid it?
這些是我正在做的步驟 - 1.加載實體 2.更新實體上的幾個字段。 3.saveAndFlush
我看到一個更新查詢,在步驟#2 中更新了所有 3 個字段。 其他更新查詢正在更新 3 個字段之一,但該值來自 Step#1 而不是 Step#2。
有人可以幫我弄清楚如何避免這種情況嗎?
編輯-添加了我的課程。
@Entity
@DynamicUpdate
public class Enrollment
{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Embedded
private Section sectionInformation = new Section();
@ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.REFRESH})
@JoinColumn(name = "student_id")
private Student student;
@Enumerated(EnumType.STRING)
private TakingExam takingExam;
}
public ResponseEntity controllerMethod(){
Enrollment enrollment = service.getEnrollment(enrollmentId);
if (enrollment == null)
{
return new ResponseEntity<>(NOT_FOUND);
}
Enrollment otherEnrollment = null;
if (check some condition)
{
otherEnrollment =
service.getEnrollment(request.someValue());
validator.validateOtherEnrollment(enrollment,
otherEnrollment, request.someValue());
}
enrollment.takingExam(request.getTakingExam());
if (otherEnrollment != null)
{
service.swapEnrollments(enrollment, otherEnrollment);
}
}
private void swapEnrollments(Enrollment enrollment, String userName){
///lots of validations
enrollment.setUpdatedBy(userName);
fromEnrollment.setUpdatedDate(new
Timestamp(System.currentTimeMillis()));
enrollmentRepo.saveAndFlush(enrollment); ---- THIS IS WHERE I SEE 2 UPDATE QUERIES AS PUT BELOW
}
update
enrollment
set
taking_exam=?,
updated_by=?,
updated_date=?
where
id=?
update
enrollment
set
taking_exam=?
where
這就是我的代碼中發生的事情 -
這有助於避免中間自動刷新
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