JPA self mapped entity with ManyToOne issue

Question

I have MySQL table with readonly access oc_category (table from Opencart).

With the next records:

id | parent_id  | Category
------------------------------
1  |     0      | TOPCategory1
2  |     0      | TOPCategory2
3  |     1      | Category1
4  |     1      | Category2

But this table doesn't have record with id - 0, but have parent_id with 0 - this mean that this category doesn't have parent category.

I have entity:

@Entity
@Table(name = "oc_category")
public class Category  {
    @Id
    @Column(name = "category_id")
    private Integer categoryId;


    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "parent_id")
    private Category parent;

    @OneToMany(mappedBy = "parent")
    private List<Category> childCategory = new ArrayList<>();

    // other fields, constructor, getters and setters.
}

When I try to get records I recieved error that I don't have record with id 0. :(

"Unable to find opencart.Category with id 0; nested exception is javax.persistence.EntityNotFoundException: Unable to find opencart.Category with id 0"

Please help resolve this issue.

Possible duplicate of [Hibernate handle long 0 value instead of NULL in ManyToOne relations](http://stackoverflow.com/questions/8038737/hibernate-handle-long-0-value-instead-of-null-in-manytoone-relations) — Sergey Vyacheslavovich Brunov, Oct 08 '16 at 00:06
Thank you Sergey, I use @ManyToOne(cascade = CascadeType.ALL) @JoinFormula(value="CASE parent_id WHEN 0 THEN NULL ELSE parent_id END") private Category parent; Problem resolved — Oleg Kovalyk, Oct 08 '16 at 09:52

JPA self mapped entity with ManyToOne issue

0 Answers0