Hibernate为自身创建外键

Question

我现在对hibernate有一个很奇怪的问题。在一个表上，它创建了一个引用它自己的外键。该列也是主键。这基本上阻止了我从表中删除任何行。

在日志中我可以看到一行字：

@Entity(name = "Device")
public class Device extends DomainObject implements Searchable {

    @Id
@GeneratedValue(strategy = GenerationType.AUTO)
protected long id;

    @Column(name = "Type")
    @Enumerated(EnumType.STRING)
    private DeviceTypeEnum type = DeviceTypeEnum.AccessControlDevice;

    @Column(name = "Name", length = Constance.DATABASE_NAME_FIELD_LENGTH)
    private String name;

    @Column(name = "Description", length = Constance.DATABASE_DESCRIPTION_FIELD_LENGTH)
    private String description;

    @Column(name = "Identifier", length = Constance.DATABASE_IDENTIFIER_FIELD_LENGTH, unique = true)
    private String identifier;

    @ManyToMany
    @JoinTable(name = "Device2Group", joinColumns = {@JoinColumn(name = "DeviceID")}, inverseJoinColumns = {@JoinColumn(name = "DeviceGroupID")})
    private List<DeviceGroup> groups = new ArrayList<DeviceGroup>();

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "location")
    private Location location;

    @ManyToOne(cascade = {CascadeType.ALL})
    @JoinColumn(name = "Address")
    private Address address;


    @ManyToOne
    @JoinColumn(name = "Link", nullable = false)
    private Link link;
}

Answer 1

结果是，在设备实体引用的一个实体类“Location”中，它有一个@ManyTomany映射的设备集合，在那里它应该是@OneTomany。将@ManyTomany更改为@OneTomany后，约束将消失。