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我的 RavenDB 数据库中有两个不同的文档集合 - Teams 和 Matches。文件如下所示:

public class Team {
    public string Id { get; set; }
    public string Name { get; set; }
    public int LeaguePosition { get; set; }
}

public class Match {
    public string Id { get; set; }
    public string HomeTeamName { get; set; }
    public string AwayTeamName { get; set; }
    public DateTime StartTime { get; set; }
}

所以基本上我有球队和这些球队之间的比赛。但是,对于某些操作,我需要从数据库中获取一个类似于以下内容的实体:

public class MatchWithExtraData {
    public string Id { get; set; } // Id from the match document.
    public string HomeTeamId { get; set; }
    public string HomeTeamName { get; set; }
    public int HomeTeamPosition { get; set; }
    public string AwayTeamId { get; set; }
    public string AwayTeamName { get; set; }
    public int AwayTeamPosition { get; set; }
    public DateTime? StartTime { get; set; }
}

我想要的是真正的比赛文件,但有主客场球队的 id 和联赛位置的额外字段。基本上用两份球队文件加入主客队名称的比赛文件,一份用于主队,一份用于客队。我认为多映射/减少索引应该可以解决问题,所以我从以下索引开始:

public class MatchWithExtraDataIndex: AbstractMultiMapIndexCreationTask<MatchWithExtraData> {
    public MatchWithExtraData() {
        AddMap<Team>(
            teams => from team in teams
                     select new {
                         Id = (string)null,
                         HomeTeamId = team.Id,
                         HomeTeamName = team.Name,
                         HomeTeamPosition = team.LeaguePosition,
                         AwayTeamId = team.Id,
                         AwayTeamName = team.Name,
                         AwayTeamPosition = team.LeaguePosition,
                         StartTime = (DateTime?)null
                     }
        );
        AddMap<Match>(
            matches => from match in matches
                       select new {
                           Id = match.Id,
                           HomeTeamId = (string)null,
                           HomeTeamName = match.HomeTeamName,
                           HomeTeamPosition = 0,
                           AwayTeamId = (string)null,
                           AwayTeamName = match.AwayTeamName,
                           AwayTeamPosition = 0,
                           StartTime = match.StartTime
                       }
        );
        Reduce = results => from result in results
                            // NOW WHAT?
    }
}

减少部分是我无法弄清楚的部分,因为每场比赛有两支球队。我想我需要先在 HomeTeamName 上,然后在 AwayTeamName 上做一个嵌套组,但我不知道该怎么做。

也许这更像是一个 LINQ 问题而不是 RavenDB 问题。但是这样一个嵌套的 group by 语句会是什么样子呢?或者可以通过其他方式完成吗?

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1 回答 1

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你最好使用转换结果,或者包含。请参阅此处的文档:http ://ravendb.net/docs/client-api/querying/handling-document-relationships

于 2013-01-28T22:57:09.597 回答