Java Hibernate映射抛出约束冲突

我有一个需要多对多映射的数据库结构。我使用@ManyToMany注释实现了它，如下所示：

@Entity
@Table(name="trans.documentfiles")
public class DocumentFile extends GenericEntity
{
    private DocumentType documentType;
    private DocumentFormat documentFormat;
    private Set<DocumentGroup> docgroups;

    /**
     * @return the documentType
     */
    @ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.ALL)
    @JoinColumn(name = "filetypeid", nullable = false)
    public DocumentType getDocumentType()
    {
        return documentType;
    }
    /**
     * @param documentType the documentType to set
     */
    public void setDocumentType(DocumentType documentType)
    {
        this.documentType = documentType;
    }
    /**
     * @return the docgroups
     */
    @ManyToMany(mappedBy = "files")
    public Set<DocumentGroup> getDocgroups()
    {
        return docgroups;
    }
    /**
     * @param docgroups the docgroups to set
     */
    public void setDocgroups(Set<DocumentGroup> docgroups)
    {
        this.docgroups = docgroups;
    }
}

请让我知道怎么做

谢谢

编辑：：

1:35:11.706 E|SqlExceptionHelper                      |The DELETE statement conflicted with the REFERENCE constraint "FK_documentfiles_documenttype". The conflict occurred in database "DMS", table "trans.documentfiles", column 'filetypeid'.

---

什么是堆栈跟踪？有指针吗？？任何提示？？抛出异常是因为您试图删除受外键约束的记录，根据我的说法，这是不好的行为。

@Override
public boolean deleteOnlyLinks(long documentId, String nodeId)
{
    Criteria docFile = null;
    try
    {
        docFile = getCriteria(DocumentGroup.class);
        docFile.createAlias("files", "file");
        docFile.add(Restrictions.eq("file.id", documentId));
        docFile.add(Restrictions.eq("nodeId", nodeId));
        List<DocumentObjectLink> lst =  docFile.list();
        /*for (DocumentObjectLink documentObjectLink : lst)
        {*/
            getCrntSession().delete(lst.get(0));
        //}
    } catch (Exception e)
    {
        logger.debug("Error while deleting" + documentId);
        throw new DMSException("Error while deleting" + documentId,ErrorCode.DELETE,e);
    }
    return true;
}

1:35:11.706 E|SqlExceptionHelper                      |The DELETE statement conflicted with the REFERENCE constraint "FK_documentfiles_documenttype". The conflict occurred in database "DMS", table "trans.documentfiles", column 'filetypeid'.