Hibernate ManyToMany Delete

Question

I have some trouble on deleting a content when is present a many to many relation with another object.

To perform delete I have an array of named query and to delete, I loop through the array and perform delete, entity per entity, like this:

private static final String[] DELETE_CONTENT_QUERY_NAMES = {
    "Entity1.deleteByContentId",
    "Entity2.deleteByContentId",
    "Entity3.deleteByContentId",
    "Entity4.deleteByContentId",
    "Entity5.deleteByContentId",
    "EntityWithManyToMany.deleteByContentId",
    "Entity7.deleteByContentId",
    "Content.DeleteByContent"
}; 

@Override
@Transactional
public void deleteContent(Content content) throws Exception{
    Map<String, Object> params = new HashMap<String, Object>();
    params.put("contentId", content.getContentId());
    for (String queryName : DELETE_CONTENT_QUERY_NAMES) {
        dao.batchDeleteByNamedQuery(queryName, params);
    }
}

When iteration try to perform EntityWithManyToMany.deleteByContentId HQL batch query, I can see on the logs the translated sql instruction, but followed by a set of insert of the same row and MySQL rightly returns me a constraint error.

This is my many to many relation object I try to delete:

@Entity
@Embeddable
public class CategoryContent implements java.io.Serializable {

    /***
     *  Private Declarations
     */
    @EmbeddedId
    @AttributeOverrides({
         @AttributeOverride(name = "contentId", column = @Column(
                name = "CONTENT_ID", 
                nullable = false, precision = 10, scale = 0)), 
         @AttributeOverride(name = "categoryId", column = @Column(
                name = "CATEGORY_ID",
                nullable = false, precision = 10, scale = 0))
    })
    @NotNull
    private CategoryContentId id;

    @ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.PERSIST)
    @JoinColumn(name = "CATEGORY_ID", insertable=false, updatable=false)
    private Category category;

    @ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.PERSIST)
    @JoinColumn(name = "CONTENT_ID", insertable=false, updatable=false)
    private Content content;

    @Column(name = "PRIORITY", nullable = true)
    private Integer priority;
}

Do you think it's possible the problem concern CascadeType? How can I solve this?

Any suggestions are appreciated!

Thanks a lot, Davide.

Answer 1

You're on the right track - try amending your cascade to

cascade = {CascadeType.PERSIST, CascadeType.DELETE}

This should work because you have a Join table.