java - Hibernate 两父一子映射

Question

我有以下场景:有公司和员工。每个公司都有一组员工。每个员工可以为多家公司工作。所以我实现了以下关系:

公司类:

@JoinTable(name = "company_employee", joinColumns = @JoinColumn(name = "company_id") , inverseJoinColumns = @JoinColumn(name = "employee_id") )
@ManyToMany(fetch = FetchType.LAZY)
private List<Employee> employees;

员工类:

@JoinTable(name = "company_employee", joinColumns = @JoinColumn(name = "employee_id") , inverseJoinColumns = @JoinColumn(name = "company_id") )
@ManyToMany(fetch = FetchType.LAZY)
private List<Company> companies;

显然，要为多家公司工作，每个员工都应该为他或她工作的每个公司分配多个不重叠的时间表。此外，每个公司-员工组合都应该有一个时间表列表，因为有时旧时间表会过期，而新时间表会生效。所以我也有 Schedule.class ，应该有 child to parent @ManyToOne与 Company 的关系和 Employee ，并且应该按照以下方式工作:每个 Schedule ，因此，List<Schedule>应该恰好对应于 Company 的一个组合和 Employee实例。如何实现这种关系？

更新 1

我只想添加 @OneToMany Schedule与每个关系 Company和 Employee ，但是我需要放置 Schedule 的实例都到Company和 Employee每次，这种方式看起来都不对，现在我也不清楚如何取回它。因此，我们将不胜感激。

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这篇文章已更新以展示我的真实场景，而不仅仅是类的通用 Entity1、Entity2、Entity3 名称。

更新 2

我接受了答案，但如果 Schedule 包含列表，我将无法使用它。按照我的计划，Schedule应包含 List<Vacation>知道 Vacations 的集合一年多了，List的 Days ，每个显示特定工作日的开始、休息和这一天的结束。那些Days每个Schedule也是独一无二的实例。

它应该是像下面这样的东西，但显然现在我没有 schedule_id ，那么如何将这些列表连接到 Schedule ？

@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true) 
@JoinColumn(name = "schedule_id") 
private List<Vacation> vacations;

@JoinTable(name = "schedule_week", joinColumns = @JoinColumn(name = "schedule_id") , inverseJoinColumns = @JoinColumn(name = "day_id") )
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true) 
private List<Day> week;

如何正确包含这些列表？

Answer 1

我想建议以下解决方案。

一个可嵌入类，其中包含用于特定计划的Company 和Employee。

@Embeddable
public class ScheduleOwner implements Serializable{

    @MapsId("id")
    @ManyToOne(cascade = CascadeType.ALL)
    Company c;

    @MapsId("id")
    @ManyToOne(cascade = CascadeType.ALL)
    Employee e;
}

Schedule 类嵌入了一个 ScheduleOwner 实例。

@Entity
public class Schedule {

    @EmbeddedId
    ScheduleOwner owner;

    String description;
}

Company 和 Employee 类(未对它们进行任何更改)

@Entity
public class Company {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @JoinTable(name = "company_employee", joinColumns = @JoinColumn(name = "company_id") , inverseJoinColumns = @JoinColumn(name = "employee_id") )
    @ManyToMany(fetch = FetchType.LAZY)
    private List<Employee> employees;
}


@Entity
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @JoinTable(name = "company_employee", joinColumns = @JoinColumn(name = "employee_id") , inverseJoinColumns = @JoinColumn(name = "company_id") )
    @ManyToMany(fetch = FetchType.LAZY)
    private List<Company> companies;
}

更新 1

以下是您可以如何保存和获取结果。

  Employee e1 = new Employee();
  Company c1 = new Company();
  c1.employees.add(e1);

  e1.companies.add(c1);

  ScheduleOwner so = new ScheduleOwner();
  so.c = c1;
  so.e = e1;

  Schedule s = new Schedule();
  s.owner = so;

  session.save(c1);
  session.save(e1);
  session.save(s);

  // below query will fetch from schedule, where company id = 9
  Schedule ss = (Schedule) session.createQuery("From Schedule sh where sh.owner.c.id = 9").uniqueResult();

更新 2

@Entity
public class Company {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @JoinTable(name = "company_employee", joinColumns = @JoinColumn(name = "company_id", referencedColumnName="id") 
                                        , inverseJoinColumns = @JoinColumn(name = "employee_id", referencedColumnName="id"))
    @ManyToMany(fetch = FetchType.LAZY)
    List<Employee> employees = new ArrayList<>();

    String name;
}

@Entity
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @ManyToMany(fetch = FetchType.LAZY, mappedBy = "employees")
    List<Company> companies = new ArrayList<>();

    String name;
}

@Entity
public class Schedule {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    int schedule_id;

    @ManyToOne
    @JoinColumn(name = "company_id", insertable = false, updatable = false)
    private Company company;
    @ManyToOne
    @JoinColumn(name = "employee_id", insertable = false, updatable = false)
    private Employee employee;

    String description;

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "schedule")
    List<Vacation> vacations;

}

@Entity
public class Vacation {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int vacation_id;

    @ManyToOne
    @JoinColumn(name = "schedule_id" ) 
    Schedule schedule;

    @OneToMany(mappedBy = "vacation")
    List<Day> days;
}

Day 实体直接与 Vacation 相关。不安排。

@Entity
public class Day {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;


    @ManyToOne
    @JoinColumn(name = "vacation_id")
    Vacation vacation;
}

希望这对您有所帮助。