如何在Ebean中对相关实体进行排序？ [英] How can I sort related entities in Ebean?

问题描述

我正在使用Play Framework和Ebean ORM。说，我有2个相关的实体类（Card.java和FinalMark.java）

I am using Play Framework and Ebean ORM. Say, I have 2 related entity classes (Card.java and FinalMark.java)

Card.java

Card.java

@Entity
public class Card extends Model {

  private static final long serialVersionUID = 1L;
  @Id
  . . .
  @OneToMany(mappedBy = "card")
  public List<FinalMark> finalMarks;
  . . .
  public static Finder<Integer, Card> find =
    new Finder<>(Integer.class, Card.class);

}

FinalMark.java

FinalMark.java

@Entity
public class FinalMark extends Model {

  private static final long serialVersionUID = 1L;
  @Id
  @ManyToOne
  public Card card;
  . . .
  public static Finder<Integer, FinalMark> find = new Finder<>(Integer.class,
    FinalMark.class);
}

当我拿到卡 instance（例如，通过Card.find.byId（）），也将获取所有相关的 FinalMark 实例。但我怎么能对它们进行排序呢？ Ebean或者我应该对结果列表进行排序吗？

When I fetching Card instance (by Card.find.byId() for example), All related FinalMark instances also will be fetched. But how can I sort them? Is it possible by Ebean or I should sort resulting list?

感谢您浪费时间。

推荐答案

您可以在 @OneToMany 上添加 @javax.persistence.OrderBy 注释字段。

You can add the @javax.persistence.OrderBy annotation on your @OneToMany field.

例如，如果您的 FinalMark上有位置字段实体，您可以使用以下代码在该字段上订购：

For example, if you have a position field on your FinalMark entity, you could order on that field with this code :

@Entity
public class Card extends Model {
    ...
    @OneToMany(mappedBy = "card")
    @OrderBy("position asc")
    public List<FinalMark> finalMarks;
    ...
}

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