Question

我有一个grails域hasMany和belongsTo关系，如下所示：

我想根据“提交”排序＆＃39; ＆＃39; LASTUPDATED＆＃39; ＆＃39;降序＆＃39;

class User {
  String username
  String password

  static hasMany = [ submissions: Submission ]

  static mapping = {
     sort submissions: 'desc'  // This doesn't do anything?
  }
}

class Submission {
  String reference
  Date dateCreated
  Date lastUpdated

  static belongsTo = User
}

所以每当我收集用户提交的内容时，我希望它默认排序为lastUpdated desc。等效的mysql语句将是以下

select (fields) from submission order by last_updated desc;

我错过了什么吗？

非常感谢！

Answer 1

我认为你应该阅读如何set default sort order in assosiation

Answer 2

因为这是单向关系，所以以下解决方案完美无缺！

class User {
  String username
  String password

  SortedSet submissions

  static hasMany = [ submissions: Submission ]

}

class Submission implements Comparable {
  String reference
  Date dateCreated
  Date lastUpdated

  static belongsTo = User

  @Override
  public int compareTo(obj) {
        obj.lastUpdated.compareTo(lastUpdated)
  } 

}

grails域默认按上次更新字段排序

2 个答案: