Hibernate 5.2在表postgres上級聯刪除

Question

我有兩個相互依賴的類。 我想進行級聯刪除。 問題我有以下錯誤：

無法執行語句； SQL [n / a]； 約束[fk5o18odcs53r4t69hbgf35haj3]; 嵌套的異常是org.hibernate.exception.ConstraintViolationException：無法執行語句

public class Workspace {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false, updatable = false)
    private Long id;

    @Column(name = "name", nullable = false, unique = true)
    private String name;

    private String description;

    @CreationTimestamp
    @Column(name = "created_at")
    private Date createdAt;

    @UpdateTimestamp
    @Column(name = "updated_at")
    private Date updatedAt;

    @OneToMany( fetch = FetchType.LAZY,cascade = CascadeType.REMOVE,orphanRemoval = true)
    private List<Project> projects;


    public void setId(Long id) {
        this.id = id;
    }

    public List<Project> getProjects() {
        return projects;
    }


    public void setProjects(List<Project> projects) {
        this.projects = projects;
    }

}

@Entity
@Table(name = "project")
public class Project {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id", nullable = false, updatable = false)
private Long id;

@Column(name = "name", nullable = false)
private String name;

@ManyToOne(fetch = FetchType.LAZY)
private Workspace workspace;

private String description;

@CreationTimestamp
@Column(name = "created_at")
private Date createdAt;

@UpdateTimestamp
@Column(name = "updated_at")
private Date updatedAt;

問題是用我的JPA創建的表沒有在刪除規則中定義級聯類型。 我是否必須直接通過sql定義約束類型？ JPA Hibernate可以不定義這些約束嗎？

Answer 1

您需要為Workspace類OneToMany關系指定mapBy參數。

@OneToMany( fetch = FetchType.LAZY,cascade = CascadeType.REMOVE,orphanRemoval = true, mappedBy = "workspace") 
private List<Project> projects;

之后，您可以刪除工作區，所有項目也將被刪除。