如何防止插入不存在的FK

Question

为什么我可以插入主题表中不存在的FK数据库（帖子表）？

@Entity
class Post(@Id
       @GeneratedValue(strategy = GenerationType.IDENTITY)
       val id: Long = 0,

       @Column(nullable = false)
       val message: String = "",

       val tpc_id: Long = 0
)

@Entity
class Topic (@Id
         @GeneratedValue(strategy = GenerationType.IDENTITY)
         val id: Long = 0,

         @Column(nullable = false)
         val title: String = "",

         val description: String = "",

         @OneToMany(fetch = FetchType.LAZY)
         @JoinColumn(name = "tpc_id", nullable = false, insertable = false, updatable = false)
         val posts: List<Post>
)

当我说带有ID的主题时：1、2、3为什么在帖子中我可以添加引用主题ID（即10）的帖子？