无法删除或更新父行：foreign key约束在联接表中失败

Question

尝试删除job对象时出现以下错误：

com.mysql.jdbc.exceptions.jdbc4.mysqlintegrityConstraintViolationException：无法删除或更新父行：外键约束失败(www.subcategory，constraintfk_subcategory_category外键(category_id)在删除时引用category(category(id)不执行更新时不执行任何操作）

表格

+============+   +=================+   +================+
| job        |   |  job_category   |   |  category      |
+============+   +=================+   +================+
| ID         |   |  JOB_ID         |   |  ID            |
|            |   |  CAT_ID         |   |                |
+============+   +=================+   +================+

                 +==================+   +=================+
                 | job_subcategory  |   | subcategory     |   
                 +==================+   +=================+
                 |  JOB_ID          |   |  ID             |
                 |  SUBCAT_ID       |   |  CATEGORY_ID    |
                 +==================+   +=================+

作业可以有许多类别。一个类别可以有许多子类别。

job.java

@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinTable(name = "job_category", joinColumns = {
        @JoinColumn(name = "JOB_ID", referencedColumnName = "ID") }, inverseJoinColumns = {
                @JoinColumn(name = "CAT_ID", referencedColumnName = "ID") })
private Set<Category> categories;

@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinTable(name = "job_subcategory", joinColumns = {
        @JoinColumn(name = "JOB_ID", referencedColumnName = "ID") }, inverseJoinColumns = {
                @JoinColumn(name = "SUBCAT_ID", referencedColumnName = "ID") })
private Set<SubCategory> subCategories;

@JsonIgnore
@OneToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER, mappedBy = "category")
private Set<SubCategory> subCategories;

@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name = "CATEGORY_ID")
private Category category;

protected void remove(Job entity) {
    entityManager.remove(entity);
}

删除job对象时，希望它从job表和联接表(job_category和job_subcategory)中删除一行，但不删除category和subcategory表。

感谢任何建议。

更新

public boolean delete(Job job) {
    Set<SubCategory> subCategories = job.getSubCategories();
    if (subCategories != null) {
        for (SubCategory subCategory : subCategories) {
            entityManager.remove(subCategory);
        }
    }
    Set<Category> categories = job.getCategories();
    if (categories != null) {
        for (Category category : categories) {
            entityManager.remove(category);
        }
    }
    entityManager.remove(job);
    return true;
}

无法删除或更新父行：外键约束失败(www。job_subcategory，约束fk_job_subcategory外键(subcat_id)在删除时引用subcategory(id，在更新时没有操作）

该错误只在我完成事务(@transactional)时发生，因此看起来就像是在Hibernate执行提交时发生的。

更新

我尝试以下方法：

public boolean delete(Job job) {
    job.setSubCategories(null);
    job.setCategories(null);
    super.remove(job);
    return true;
}

但再次获得以下内容：

public boolean delete(Job job) {
    job.setSubCategories(null); 
    job.setCategories(null);
    job.setPerson(null);        
    super.remove(job);
    return true;
}

Answer 1

好吧，试试看

public boolean delete(Job job) {
    Set<SubCategory> subCategories = job.getSubCategories();
    if (subCategories != null) {
        job.getSubCategories().clear();
        for (SubCategory subCategory : subCategories) {
            subCategory.setJob(null);
            entityManager.remove(subCategory);
        }
    }
    Set<Category> categories = job.getCategories();
    if (categories != null) {
        job.getCategories().clear();
        for (Category category : categories) {
            category.setJob(null);
            entityManager.remove(category);
        }
    }
    job.setPerson(null);
    //if necessary:
    //Person.setJob(null);        
    entityManager.remove(job);
    return true;
}

另外，为什么您有super.remove(job)，而没有EntityManager.remove(job)，就像我刚刚发布的代码那样？

这段代码是否仍有异常？