我有实体Unit,Employee,我想要映射到Unit中的Employee列表。
示例SQL:
select e.*
from wfm.WFM_EMPLOYEE e
join wfm.wfm_position2unit p2u on p2u.UNIT_POSITION_ID=e.unit_position_id
join wfm.WFM_POSITION p on p.POSITION_ID=p2u.POSITION_ID
join wfm.wfm_unit u on u.UNIT_ID=p2u.UNIT_ID
where u.unit_id = 337
现在我可以通过'嵌套'@OneToMany注释访问员工:
单位:
@Entity
@Table(name = "WFM_UNIT", schema = AppData.WFM_SCHEMA)
public class Unit implements Serializable {
...
@OneToMany(mappedBy = "unit", fetch = FetchType.EAGER)
private List<Position2unit> position2units;
...
}
PositionToUnit:
@Entity
@Table(name = "WFM_POSITION2UNIT", schema = AppData.WFM_SCHEMA)
public class Position2unit implements Serializable {
...
@ManyToOne(fetch = FetchType.LAZY, optional = true)
@JoinColumn(name = "POSITION_ID")
private Position position;
@ManyToOne(fetch = FetchType.LAZY, optional = true)
@JoinColumn(name = "UNIT_ID")
private Unit unit;
@OneToMany(mappedBy = "position2unit", fetch = FetchType.LAZY)
private List<Employee> employees;
...
}
员工:
@Entity
@Table(name = "WFM_EMPLOYEE", schema = AppData.WFM_SCHEMA)
public class Employee implements Serializable {
...
@NotFound(action = NotFoundAction.IGNORE)
@ManyToOne(fetch = FetchType.LAZY, optional = true)
@JoinColumn(name = "UNIT_POSITION_ID")
private Position2unit position2unit;
...
}
答案 0 :(得分:1)
我认为到目前为止最简单的解决方案是向Unit添加一个方法:
Collection<Employee> getEmployees() {
final Collection<Employee> employees = new HashSet<Employee>();
for (final Position2unit p2u : position2units) {
employees.addAll(p2u.employees);
}
return employees;
}
并完全忘记了映射。