java - Hibernate 为自己创建外键

Question

我现在有一个非常奇怪的 hibernate 问题。它以某种方式在表上创建了一个引用自身的外键。该列也是一个主键。这实质上阻止了我从该表中删除任何行。

在日志中我可以看到一行:

DEBUG org.hibernate.SQL - alter table Device add index FK79D00A76C682495E (id), add constraint FK79D00A76C682495E foreign key (id) references Device (id)

具有类似表的其他表似乎没问题。这似乎对 MySQL 和 Derby 都是如此。我正在使用 hibernate 4.1.4

注解类如下。

@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

事实证明，在 Device 实体引用的实体类“Location”之一中，它有一个 @ManyToMany 映射的 Device 集合，它实际上应该是 @OneToMany。将 @ManyToMany 更改为 @OneToMany 后，约束消失。