c# – 使用子集合在RavenDb中映射2个集合
发布时间:2020-12-15 08:34:13 所属栏目:百科 来源:网络整理
导读: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": [ "tag
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(); (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |