JPA如何使复合主键的复合外键部分

我有以下表格如何将它们映射到JPA实体：

TABLE Event { EventID SourceID ....Other event fields PK (EventID, SourceID) } TABLE MEETING { MeetingID EventID SourceID ...Other meeting fields PK(MeetingID,EventID, SourceID) FK(EventID, SourceID) //FK with Event table } 

Event表与Meeting表具有一对多的关系。 我如何在JPA中映射这种双向关系？

Answer 1

 @Embeddable public class EventID { public int eventID; public int sourceID; } @Entity public class Event { @EmbeddedId public EventID id; @OneToMany(mappedBy="event") public Collection meetings; } @Embeddable public class MeetingID { public EventID eventID; // corresponds to ID type of Event public int meetingID; } @Entity public class Meeting { @EmbeddedId public MeetingID id; @MapsId("eventID") @JoinColumns({ @JoinColumn(name="EventID", referencedColumnName="EventID"), @JoinColumn(name="SourceID", referencedColumnName="SourceID") }) @ManyToOne public Event event; } 

在JPA 2.1规范，第2.4.1节中讨论。

Answer 2

 @Entity public class Event { @EmbeddedId private EventId id; @OneToMany(mappedBy = "event") private List meetings = new ArrayList<>(); } @Embeddable public class EventId implements Serializable { @Column(name = "EventID") private Long eventId; @Column(name = "SourceID") private Long sourceId; //implements equals and hashCode } @Entity public class Meeting { @EmbeddedId private MeetingId id; @MapsId("eventId") @JoinColumns({ @JoinColumn(name="EventID", referencedColumnName="EventID"), @JoinColumn(name="SourceID", referencedColumnName="SourceID") }) @ManyToOne private Event event; } @Embeddable public class MeetingId implements Serializable { @Column(name = "MeetingID") private Long meetingId; private EventId eventId; //implements equals and hashCode } 

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