hql和@EmbeddedId

Question

是否可以從查詢中查詢Embeddable對象？這裏是我的實體：

@Entity 
@Table(name = "A") 
public class UnitParam implements Serializable { 
    ... 
    @EmbeddedId 
    private UnitParamId unitParamId; 
    .... 
} 

@Embeddable 
public class UnitParamId implements Serializable { 

    @Column(name = "PcID", nullable = false) 
    private short pcId; 

    @Column(name = "UnitID", nullable = false) 
    private short unitId; 

    @Column(name = "ParamID", nullable = false) 
    private int paramId; 
    ... 
} 

@Entity 
@Table(name = "B") 
public class ParameterMapping extends BasicEntity { 

    @ManyToOne(fetch = FetchType.LAZY) 
    @JoinColumns(value = { 
     @JoinColumn(name = "PcID", referencedColumnName = "PcID"), 
     @JoinColumn(name = "UnitID", referencedColumnName = "UnitID"), 
     @JoinColumn(name = "ParamID", referencedColumnName = "ParamID") }) 
    private UnitParam unitParam; 
... 
} 

這裏是一個失敗的查詢：

select p.id, p.name as name, 
    p.unitParam.unitParamId.pcId as processCell, 
    p.unitParam.unitParamId.unitId as unit, 
    p.unitParam.unitParamId.paramId as paramId 
    from ParameterMapping p 

不同之處：org.hibernate.QueryException：由造成無法解析屬性：unitParamId的： ParameterMapping [選擇p.id，作爲名稱的p.name，p.unitParam.unitParamId.pcId作爲processCell，p.unitParam.unitParamId.unitParam.unitId作爲單位， p.unitParam.unitParamId.paramId作爲paramId FROM de.koehl .mes.model.ParameterMapping p]


預先感謝您。

我發現問題：第一個問題是混合字段/屬性訪問。修復之後，ManyToOne會生成列，但不會有外鍵！但我不知道爲什麼！

Answer 1

UnitParamId中沒有unitParam字段，所以路徑p.unitParam.unitParamId.unitParam.unitId無效。您的查詢更改爲

select p.id, p.name as name, 
     p.unitParam.unitParamId.pcId as processCell, 
     p.unitParam.unitParamId.unitId as unit, 
     p.unitParam.unitParamId.paramId as paramId 
from ParameterMapping p 

甚至更​​好：

select p.id, p.name as name, 
     unitParam.unitParamId.pcId as processCell, 
     unitParam.unitParamId.unitId as unit, 
     unitParam.unitParamId.paramId as paramId 
from ParameterMapping p 
inner join p.unitParam unitParam