Question

很多时候我在我的实体中使用@Formula。但总是这是一个简单的查询或带参数的存储过程，我可以从表中提取。现在我需要从相关对象中使用一些属性。但是当我尝试从DB获取对象时，我看到异常。请参阅下面的示例

@Entity
@Table(name = "MINISTRY")
public class Ministry {

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

    @Column(name = "NAME")
    private String name;

    // unnecessary code

}

@Entity
@Table(name = "DEPARTMENT")
public class Department {

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

    @Column(name = "DEP_NAME")
    private String departmentName;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "MINISTRY_ID")
    private Ministry ministry;

    // unnecessary code
}

@Entity
@Table(name = "EMPLOYEE")
public class Employee {

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

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "DEPARTMENT_ID")
    private Department department;

    @Formula("test_package.calc_something(department.ministry.id)")
    private BigDecimal someMetric;

    // unnecessary code

}

我应该如何在@Formula中使用实体道具。我不想写像

这样的东西

select d.ministry.id from Department d ...

如何在Hibernate @Formula中使用实体字段

0 个答案: