Hibernate 实体级联删除父级或子级

Question

我有一些关于 "cascade" 的问题，在我的项目中，我有类别 class 并且每个 class 都可以是父项或 child.But 我在相同的 class 中定义哪个父项或 child.There 是一个-父子之间的一对多关系。这是我的实体 class

import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import org.hibernate.annotations.*;

import javax.persistence.*;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

@Getter
@Setter
@EqualsAndHashCode(exclude = {"recipes","categories","parentCategory","childrenCategory"})
@Entity
public class Category implements Serializable {
    private static final long serialVersionUID = 1L;

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

    private String categoryName;

    private String categoryDescription;

    private String categoryUrl;


    @OneToMany(mappedBy = "parentCategory",cascade = CascadeType.ALL)
    private Set<Category> childrenCategory = new HashSet<>();

    @ManyToOne
    private Category parentCategory;

    private boolean menuActive;

    @ManyToMany(mappedBy = "categories")
    Set<Recipe> recipes = new HashSet<>();

    public Category addChildren(Category category){
        this.getChildrenCategory().add(category);
        category.setParentCategory(this);
        return this;
    }

}

我的问题是；当我删除子类别时没问题，如果父类别有子类别，它 success.I 不能删除父类别。

错误信息；

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint ["FKBPI63NYEL12J6UG0D7S6BUAKX: PUBLIC.CAT_RECIPE FOREIGN KEY(CATEGORY_ID) REFERENCES PUBLIC.CATEGORY(ID) (5)"; SQL statement: delete from category where id=? [23503-197]]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause

如何删除父类别？

解决方案

public void removeChildren(Category childCategory){
    childCategory.setParentCategory(null);
}

你可以打电话给

category.get().getChildrenCategory().forEach(category.get()::removeChildren);

Answer 1

这是双向关系。所以你需要从双方删除关联。像这样：

public void removeChildren(Category childCategory){
    this.getChildrenCategory().remove(childCategory);
    childCategory.setParentCategory(null);
}

然后

parentCategory.getSubCategories().forEach(parentCategory::remove);

现在您可以删除 parentCategory。

Hibernate 实体级联删除父级或子级

Hibernate entity cascade deletion parent or child

java

spring

hibernate

jpa

cascade