我可以在多对多关系中的连接表中添加非Id字段吗？

Question

我在CREATE TABLE INSERT 0 4 PREPARE name | age | salary -------+-----+-------- Alice | 13 | 3 (1 row) name | age | salary -------+-----+-------- Alice | 13 | 3 (1 row) 和function Pyth(lat1,lat2,lng1,lng2){ x = toRad(lng2-lng1) ; y = toRad(lat2-lat1); R = 6371000; // gives d in metres d = sqrt(x*x + y*y) * R; return d; } 表之间有多对多的关系。

人：

Person

地址：

Address

我有一个名为@Entity @Table(name = "PERSON_MTM", schema = "Examples") public class Person { @Id @Column(name = "PERSON_ID") private String personId; @Column(name = "PERSON_NAME") private String personName; @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY) @JoinTable(name = "PERSON_ADDRESS", schema = "KunderaExamples",joinColumns = { @JoinColumn(name = "PERSON_ID") }, inverseJoinColumns = { @JoinColumn(name = "ADDRESS_ID") }) private Set<AddressMTM> addresses; //setters and getters } 的 joinTable 。

• 我可以将非Id字段添加到join-table吗？
• 是否有任何JPA限制？

  

注意：我的问题不在于@Entity @Table(name = "ADDRESS_MTM", schema = "Examples") public class Address { @Id @Column(name = "ADDRESS_ID") private String addressId; @Column(name = "STREET") private String street; // setters and getters } 。我在问   代表PERSON_ADDRESS

Answer 1

您可以使用多个JoinColumms，例如包括PERSON_NAME（如果这对您的逻辑有意义）

@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinTable(
    name = "PERSON_ADDRESS", 
    schema = "KunderaExamples",
    joinColumns = { 
      @JoinColumn(name="PERSON_NAME"),
      @JoinColumn(name = "PERSON_ID") }, 
    inverseJoinColumns = {  
      @JoinColumn(name = "ADDRESS_ID") })
private Set<AddressMTM> addresses;