我正在使用Spring. jpa.hibernate.ddl-auto=update属性来更新架构。

根据我的理解，如果我们对实体进行更改，那么表模式就会更新。

但是在Spring启动应用程序启动时，每次为外键执行更改命令。

以下是实体。

@Entity
@Table(name = "feedback")
@Data
public class Feedback implements Serializable {

    private static final long serialVersionUID = -6420805626682233375L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "study_id")
    @JsonIgnore
    private Study study;

    @ManyToOne(fetch= FetchType.EAGER)
    @JoinColumn(name="user_id", nullable = false)
    private User user;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "feedback_date", nullable = false)
    private Date feedbackDate;

    @Size(max = 1000)
    @Column(name = "feedback", length = 1000)
    private String feedback;

}

在实体中，您可以看到我有以下两个属性，用于在Spring启动应用程序首次启动时创建外键：

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "study_id")
@JsonIgnore
private Study study;

@ManyToOne(fetch= FetchType.EAGER)
@JoinColumn(name="user_id", nullable = false)
private User user;

因此，当我每次重新启动应用程序或保存代码时，外键约束都会被更改，即使我没有更改该关系（属性）。

2018-12-05 18:44:12.027  INFO 22736 --- [  restartedMain] c.d.smartviewer.SmartViewerApplication   : Starting SmartViewerApplication on LAPTOP-F95LLCU3 with PID 22736 (D:\Sagar_\SVN\SmartViewer\target\classes started by ASUS in D:\Sagar_\SVN\SmartViewer)
2018-12-05 18:44:12.027 DEBUG 22736 --- [  restartedMain] c.d.smartviewer.SmartViewerApplication   : Running with Spring Boot v2.0.6.RELEASE, Spring v5.0.10.RELEASE
2018-12-05 18:44:12.027  INFO 22736 --- [  restartedMain] c.d.smartviewer.SmartViewerApplication   : No active profile set, falling back to default profiles: default
2018-12-05 18:44:13.356  INFO 22736 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1329 ms
Hibernate: alter table annotation add constraint FK7hwy1g5myfk7grmm2j7faqggd foreign key (parent_id) references annotation (id)
Hibernate: alter table feedback add constraint FKfxt8nk3jikofi3x40bsjd00vt foreign key (study_id) references study (id)
Hibernate: alter table feedback add constraint FK7k33yw505d347mw3avr93akao foreign key (user_id) references user (id)
Hibernate: alter table hospital add constraint FK3922fhj7qnyc3bw5x8xl6m6xc foreign key (contact_1) references contact (id)

那么，如果我不改变外键实体属性，我应该改变什么来不执行外键的改变命令呢？