Java Hibernate创建复合密钥而不是使用标识符

我有一个实体FooBar，它充当Foo和Bar实体的@ManyToMany联接表，包括一些附加信息

@Entity
@Table(name = "foo_bar")
public class FooBar
{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", unique = true, nullable = false)
    protected Long id;

    @Column(name = "someInfo", nullable = true)
    private String someInfo;

    @ManyToOne(optional = false)
    private Foo foo;

    @ManyToOne(optional = false)
    private Bar bar;


    //getters, setters, and toString()
}

@Entity
@Table(name = "foo")
public class Foo
{
   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   @Column(name = "id", unique = true, nullable = false)
   protected Long id;

   @OneToMany(mappedBy = "foo", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
   private Set<FooBar> fooBars;

   //Foo has a number of other fields
   @Column(name = "orderIndex", nullable = false)
   private int orderIndex;

   @Column(name = "upgradeDirection", nullable = false)
   @Enumerated(EnumType.STRING)
   private Order direction;

   @ManyToOne(optional = false)
   private SomeEntity e;


   //getters, setters, and toString()
}


@Entity
@Table(name = "bar")
public class Bar
{
   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   @Column(name = "id", unique = true, nullable = false)
   protected Long id;

   @OneToMany(mappedBy = "bar") //TODO specify a cascade and fetch attribute
   private Set<FooBar> fooBars;

   //Bar contains a number of other fields
   @Column(name = "value", nullable = false)
   private String value;


   //getters, setters, and toString()
}

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当Hibernate创建表时，表包含“id”、“someInfo”、“foo\u id”和“bar\u id”列foo_id'和'bar_id'在中用作复合键，而不是使用'id'字段，知道为什么吗？

在foo或bar中是否有@manytomy注释？foo和bar都与foobari有@OneToMany关系是否可能是在对注释进行某些更改之前生成的表？如果删除该表并让Hibernate重新创建它，会得到相同的结果吗？是的，我只删除了foo_bar并删除了整个数据库。当Hibernate创建表时，它使复合键变得非常奇怪。。。在你给我们看的代码中，我看不出是什么原因造成的。也许是因为你没给我们看的东西。