c# – 使用子集合在RavenDb中映射2个集合

我有两种不同的对象类型存储在RavenDb中,它们是父/子类型关系,在 JSON中是这样的：

Account/1
{        
    "Name": "Acc1",}

Items/1
{
    "Account": "Account/1","Value" : "100","Tags": [
       "tag1","tag2"]
}

Items/2
{
    "Account": "Account/1","Value" : "50","Tags": [
       "tag2"]
}

请注意,我不想将它们存储在同一文档中,因为一个帐户可能有数千个项目.

我正在尝试编写一个map / reduce索引,它会返回类似于：

{
    "Account": "Acc1","TagInfo": [
        { "TagName" : "tag1","Count" : "1",//Count of all the "tag1" occurrences for acc1
          "Value" : "100" //Sum of all the Values for acc1 which are tagged 'tag1'
        },{ "TagName" : "tag2","Count" : "2",//Two items are tagged "tag2"
          "Value" : "150"
        }]
}

即所有不同标签名称的列表,以及每个标签名称的数量及其值.

我想我需要使用多地图将Account和Items集合映射到一起,但我无法找出reduce部分来创建结果的“TagInfo”部分.

这是可能的,还是我在Raven模拟这个错误？

编辑：

我想从这个查询中检索的类看起来像这样：

public class QueryResult
{
    public string AccountId {get;set;}
    public TagInfo Tags {get;set;} 
}

public class TagInfo
{
    public string TagName {get;set;}
    public int Count {get;set;}
    public int TotalSum {get;set;}
}

解决方法

您不能使用Multi Map / Reduce索引,因为您需要在标签上放置一个地图而在帐户上放置另一个地图.他们没有共同的属性,所以你不能在这里有多个地图/减少.

但是,您可以使用TransformResult.这是怎么做的：

public class Account
{
    public string Id { get; set; }
    public string Name { get; set; }
}

public class Item
{
    public string Id { get; set; }
    public string AccountId { get; set; }
    public int Value { get; set; }
    public List<string> Tags { get; set; }
}

public class TagsWithCountAndValues : AbstractIndexCreationTask<Item,TagsWithCountAndValues.ReduceResult>
{
    public class ReduceResult
    {
        public string AccountId { get; set; }
        public string AccountName { get; set; }
        public string Tag { get; set; }
        public int Count { get; set; }
        public int TotalSum { get; set; }
    }

    public TagsWithCountAndValues()
    {
        Map = items => from item in items
                        from tag in item.Tags
                        select new
                        {
                            AccountId = item.AccountId,Tag = tag,Count = 1,TotalSum = item.Value
                        };
        Reduce = results => from result in results
                            group result by result.Tag
                            into g
                            select new
                            {
                                AccountId = g.Select(x => x.AccountId).FirstOrDefault(),Tag = g.Key,Count = g.Sum(x => x.Count),TotalSum = g.Sum(x => x.TotalSum)
                            };
        TransformResults = (database,results) => from result in results
                                                    let account = database.Load<Account>(result.AccountId)
                                                    select new
                                                    {
                                                        AccountId = result.AccountId,AccountName = account.Name,Tag = result.Tag,Count = result.Count,TotalSum = result.TotalSum
                                                    };
    }
}

之后,您可以像这样查询：

var results = session.Query<TagsWithCountAndValues.ReduceResult,TagsWithCountAndValues>()
    .Where(x => x.AccountId == "accounts/1")                        
    .ToList();

c# – 使用子集合在RavenDb中映射2个集合

解决方法

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