@JoinFormula and @OneToMany definition - poor documentation

问题

I have two questions concerning @JoinFormula and @OneToMany annotations:

1. How can I limit the number of result with @JoinFormula and @OneToMany annotations?

2. How can I define that id in expression author = id refers to Author.id?

   Author {
   
       @Id
       private Long id;
   
       @OneToMany
       @JoinFormula(value = "SELECT a FROM Article a WHERE author = id AND schedule < CURRENT_TIMESTAMP()") // limit = 15
       private List<Article> pastArticles;
   }
   

Like this, I keep having the pastArticles empty, even when I remove the schedule < part of the clause.

Thanks!

回答1:

Answer 1 :

@Size(max=10)
private List<Comment> commentList;

Answer 2 :(just example like that)

public class A{

    @Id
    @GeneratedValue
    private Integer id;

    private String uuid;

    ...
  }

other class

public class B{
      @Id 
      @GeneratedValue
      private Integer id;

      private String uuidOfA;



  @ManyToOne
  @JoinColumnsOrFormulas({
  @JoinColumnOrFormula(formula=@JoinFormula(value="(SELECT a.id FROM A a WHERE a.uuid = uuid)", referencedColumnName="id")),
  @JoinColumnOrFormula(column = @JoinColumn("uuidOfA", referencedColumnName="uuid"))
})

     private A a;      
}

回答2:

you'd be better off using the @Where annotation to limit the results

来源：https://stackoverflow.com/questions/9954937/joinformula-and-onetomany-definition-poor-documentation