SpringData crudepository应用于自动级联类型

在我的项目中,我必须连接到现有的数据库并执行更新两个表的逻辑。

@Entity
@Table(name = "DOCUMENTCONTENT")
@Getter
public class DocumentContent {

    @Id
    @Column(name = "ID", insertable = false, updatable = false)
    private Long id;

    @OneToOne
    @JoinColumn(name = "DOCUMENT_ID", insertable = false, updatable = false)
    private Document document;

    @Lob
    @Column(name = "CONTENT")
    @Setter
    private byte[] content;
}

@Entity
@Table(name = "DOCUMENT")
@Getter
public class Document {

    @Id
    @Column(name = "ID", insertable = false, updatable = false)
    private Long id;

    @OneToOne(mappedBy = "document")
    private DocumentContent documentContent;

    @OneToMany(mappedBy = "document", fetch = EAGER)
    private List<Attachment> attachments;
}

@Entity
@Table(name = "ATTACHMENT")
@Getter
public class Attachment {

    @Id
    @Column(name = "ID")
    private Long id;

    @ManyToOne
    @JoinColumn(name = "DOCUMENT_ID", insertable = false, updatable = false)
    private Document document;

    @ManyToOne
    @JoinColumn(name = "CONTRACT_ID",updatable = false, insertable = false)
    private Contract contract;
}

@Entity
@Table(name = "CONTRACT")
@Getter
public class Contract {

    @Id
    @Column(name = "ID", insertable = false, updatable = false)
    private Long id;

    @Column(name = "STATUS")
    @Setter
    private String status;

    @ManyToOne
    @JoinColumn(name = "CUSTOMER_ID", insertable = false, updatable = false)
    private Customer customer;

    @OneToMany(mappedBy = "contract", fetch = EAGER)
    private List<Attachment> attachments;
}

@Service
public class MyServiceImpl implements MyService {

    @Autowired
    private DocumentContentRepository documentContentRepository; // spring data Crud Repository

    @Override
    @Transactional
    public void updateDocumentContent(SomeDto someDto) {
        DocumentContent documentContent = documentContentRepository.findByDocumentId(someDto.getDocumentId());
        documentContent.setContent(someDto.getBytes());
        List<Contract> contracts = documentContent.getDocument().getAttachments()
                .stream().map(Attachment::getContract).collect(toList());
        contracts.forEach(contract -> contract.setStatus("SIGNED"));
        documentContentRepository.save(documentContent);
    }
}

当我从上述服务启动方法时,我可以注意到控制台输出中的SQL:

休眠:更新documentcontent set content=?其中id=?

我理解为什么jpa在documentcontent表中执行了第一次更新,但我不知道为什么它也在contract表中执行了更新。如你所见,我没有使用 CascadeType.MERGE 在任何实体中。

你能解释一下为什么第二次更新没有声明级联类型吗?