java - Hibernate JPA @Inheritance TABLE_PER_CLASS JpaRepository 子实体联合选择所有表

Question

我有一个问题，我有一个带有继承 TABLE_PER_CLASS 的基本抽象实体站和三个子表 StationCompany StationAnalysis StationVariant

@MappedSuperclass
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS )
public abstract class Station {

@Entity
public class StationCompany extends Station {

@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Fetch(FetchMode.SELECT)
private Company company;

@Entity
public class StationAnalysis extends StationCompany {

@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Fetch(FetchMode.SELECT)
private Analysis analysis;

@Entity
public class StationVariant extends StationAnalysis {

@ManyToOne(optional = false, fetch = FetchType.EAGER)
@Fetch(FetchMode.SELECT)
private Variant variant;

public interface IStationCompanyRepository extends JpaRepository<StationCompany, Long> {

@Service
public class StationService implements IStationService<StationCompany> {

    @Autowired
    IStationCompanyRepository stationCompanyRepository;

然后我在StationCompany上搜索findAll，hibernate使用union select进行查询。我将仅搜索 StationCompany 条目。

select x from ( select a from StationCompany union select b from StationVariant union select c from StationAnalysis )

Answer 1

问题是 hibernate 映射。我认为从车站到车站公司再到车站的结构有问题......我用额外的 Abstract @MappedSuperclass 类解决了这个问题。之后， hibernate 选择正确的表，并且不再选择联合。

@MappedSuperclass
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class Station {

@MappedSuperclass
public abstract class AbstractStationCompany extends Station {
    @ManyToOne(optional = false, fetch = FetchType.EAGER)
    @Fetch(FetchMode.SELECT)
    private Company company;

@Entity
public class StationCompany extends AbstractStationCompany {

@MappedSuperclass
public class AbstractStationAnalysis extends AbstractStationCompany {
    @ManyToOne(optional = false, fetch = FetchType.EAGER)
    @Fetch(FetchMode.SELECT)
    private Analysis analysis;

@Entity
public class StationAnalysis extends AbstractStationAnalysis {

@Entity
public class StationVariant extends AbstractStationAnalysis {