嗯，您遇到的基本问题是根据列而不是实体进行思考，尽管由于问题有点棘手，所以这可能是不公平的陈述。基本问题是如何将实体作为复合键的一部分包含在内，我在这里找到了答案：如何在JPA中创建包含@ManyToOne属性作为@EmbeddedId的复合主键？。设备：
@Entity@Table(name = "devices")public class Device{ @Id @Column(name = "device_nbr") private Long number; @Column(name = "device_id", length = 20) private String deviceId; @ManyToOne(fetch=FetchType.EAGER, cascade=CascadeType.ALL) @JoinColumns({@JoinColumn(name="dev_type", referencedColumnName="dev_type"), @JoinColumn(name="model_nbr", referencedColumnName="model_nbr")}) private DeviceModel deviceModel; // This creates a foreign key constraint, but otherwise doesn't function // deviceType must be accessed through deviceModel // note, it can be used for explicit selects, e.g., "select d.deviceType from Device d" @oneToOne(fetch=FetchType.EAGER, cascade=CascadeType.ALL) @JoinColumn(name="dev_type", referencedColumnName="dev_type", insertable=false, updatable=false) private DeviceType deviceType; @Column(name = "unit_addr", length = 32) private String unitAddress;设备型号：
@Entity@Table(name = "devmodels")public class DeviceModel{ @EmbeddedId private DeviceModelId id; @ManyToOne(fetch=FetchType.EAGER, cascade=CascadeType.ALL) @JoinColumn(name="dev_type") @MapsId("deviceType") private DeviceType deviceType; @Column(name = "model_desc", length=20) private String description;DeviceModelId：
@Embeddablepublic class DeviceModelId implements Serializable{ private static final long serialVersionUID = -8173857210615808268L; private Integer deviceType; @Column(name="model_nbr") private Integer modelNumber;请注意，我使用
@Embeddable和
@EmbeddedId。它只是更新的，我已经阅读了JPA提供程序的评论，它比首选
@IdClass。我认为这也使列命名更容易一些，但我不记得了。
设备类型：
@Entity@Table(name = "devtypes")public class DeviceType{ @Id @GeneratedValue @Column(name = "dev_type") private Integer deviceType; @Column(name = "dev_desc", length = 16) private String description;诀窍是
@MapsId在
DeviceModel。这样就可以在CompositeKey中使用实体。该字段上的@JoinColumn启用了该字段的命名。使用它的唯一技巧是手动创建DeviceTypeId：
DeviceModel model = new DeviceModel();DeviceModelId modelId = new DeviceModelId();modelId.setModelNumber(654321);// have to have a DeviceType to create a DeviceModelmodel.setDeviceType(type);model.setId(modelId);
这将创建以下模式，该模式似乎与您的模式匹配。
create table devices (device_nbr bigint not null, device_id varchar(20), unit_addr varchar(32), dev_type integer, model_nbr integer, primary key (device_nbr))create table devmodels (dev_type integer not null, model_nbr integer not null, model_desc varchar(20), primary key (dev_type, model_nbr))create table devtypes (dev_type integer not null, dev_desc varchar(16), primary key (dev_type))alter table devices add constraint FK8q0a886v04gg0qv261x1b2qrf foreign key (dev_type, model_nbr) references devmodelsalter table devices add constraint FKb72a7hq5phwjtbhaglobdkgji foreign key (dev_type) references devtypesalter table devmodels add constraint FK4xlwyd2gwpbs4g4hdckyb11oj foreign key (dev_type) references devtypes
