c# - RavenDB 索引 : Need a solution to merge 2 dictionary fields into a single dictionary, 将其展平并使其可搜索

Question

我们正在为客户构建一个嵌套的 UI View ，需要一个解决方案来将 2 个字典字段合并到一个合并的字典中，并使键像字段名称一样可搜索。我设法使用 http://ravendb.net/docs/2.5/client-api/advanced/dynamic-fields 中提到的技术创建了一个 Map/Reduce 索引。和 https://groups.google.com/forum/#!msg/ravendb/c0HdJT-yyvQ/qvkVRrZfvmgJ .

public class ViewFolderResultWithIndividualProperties
        {
            public string EntryId { get; set; }
            public List<KeyValuePair<string, string>> MetadataProperties { get; set; }            
            public List<KeyValuePair<string, string>> NamedProperties { get; set; }
            public List<KeyValuePair<string, string>> Properties { get; set; }
            public string FlattenedProperties { get; set; }
            public string _ { get; set; }       
        }

MetadateProperties – 它是键值对的字典。例如，

"MetadataProperties": [
    {
      "Key": "JobName",
      "Value": "one job"
    },
    {
     "Key": "Organization",
      "Value": "foo"
    }]

NamesProperties – 它是已知键值对的字典。例如，

"NamedProperties": [
    {
      "Key": "Tags",
      "Value": ""
    },
    {
      "Key": "Name",
      "Value": "file-184"
    },
    {
      "Key": "Uploader",
      "Value": "rmani@transper.com"
    },
    {
      "Key": "FileType",
      "Value": "Jpg"
    },
    {
      "Key": "Language",
      "Value": "English"
    }]

Properties – 它是一个合并的字典，包含来自 MetadataProperties 和 NamedProperties 的键值对。

FlattenedProperties 和 _ 是分别包含“NamedProperties”和“MetadataProperties”的扁平化字段值的属性。我想不出一种方法来展平像“Properties”这样的计算属性(它结合了 MetadataProperties 和 NamedProperties 字典)。我试过连接

这是索引创建代码:

public class PortalEntryViews_DocumentIdSplitIndex : AbstractIndexCreationTask<PortalEntry, ViewFolderResultWithIndividualProperties>
        {
            public PortalEntryViews_DocumentIdSplitIndex()
            {
                Map = portalEntries => from portalEntry in portalEntries
                                       select new 
                                                     {
                                                         EntryId = portalEntry.Id,
                                                         MetadataProperties = portalEntry.MetaData.Select(t => new KeyValuePair<string, string>(t.Key, t.Value)).ToList(),                                                         
                                                         NamedProperties = new List<KeyValuePair<string, string>> { 
                                                             new KeyValuePair<string, string>("Tags", string.Join(",", portalEntry.Tags.Where(t => !t.IsInternal).Select(t=>t.Name))),
                                                             new KeyValuePair<string, string>("Name", portalEntry.Name),
                                                             new KeyValuePair<string, string>("Uploader", portalEntry.Uploader),
                                                             new KeyValuePair<string, string>("FileType", portalEntry.FileType),
                                                             new KeyValuePair<string, string>("Language", portalEntry.Language),
                                                             new KeyValuePair<string, string>("Name", portalEntry.Name) },
                                                             Properties = new List<KeyValuePair<string, string>>(),
                                                             FlattenedProperties = "",
                                                         _ = ""                                                         
                                                     };


                Reduce = results => from result in results                                    
                                    group result by new { result.EntryId, result.MetadataProperties, result.NamedProperties, result.FlattenedProperties, result._ } into g
                                    select new
                                    {
                                        EntryId = g.Key.EntryId,
                                        MetadataProperties = g.Key.MetadataProperties,
                                        NamedProperties = g.Key.NamedProperties,
                                        Properties = g.Key.MetadataProperties.Concat(g.Key.NamedProperties).ToList(),
                                        FlattenedProperties = g.Key.NamedProperties.Select(f => CreateField(f.Key, f.Value)),
                                        _ = g.Key.MetadataProperties.Select(t => CreateField(t.Key, t.Value, true, true))
                                    };


            }
        }

当我直接从 RavenDb Explorer 运行“Language:English”这样的查询时，它会工作并返回一个投影。而当我在 C# 代码中使用 LuceneQuery 运行相同的查询时:

var entries =
                    session.Advanced.LuceneQuery<ViewFolderResultWithIndividualProperties>(
                        "PortalEntryViews/DocumentIdSplitIndex")
                        .WhereEquals("Language", "English").ToList(); 

我收到这个错误:

Raven.Imports.Newtonsoft.Json.JsonSerializationException : Could not read value for property: FlattenedProperties  ----> Raven.Imports.Newtonsoft.Json.JsonReaderException : Error reading string. Unexpected token: StartArray 

我的最终目标是使用 CreateField() 将组合字典(即属性字段)展平为单个字段，可以使用键进行搜索，就好像它们是字段名称一样。但是，如果我使用这样的调用:

Properties = g.Key.MetadataProperties.Concat(g.Key.NamedProperties).ToList().Select(t => CreateField(t.Key, t.Value, true, true))，它似乎可以运行，但是当您从 Ravendb Explorer 查看索引时，它会显示实际错误:

阶段:索引部分:Reduce 描述:“System.Collections.Generic.List”不包含“Select”的定义

现在，我只能将一个字典 (MetadataProperties) 平展到 reduce 部分的那个“_”字段中，它在 Ravendb Explorer 和 C# 代码中都可以使用 LuceneQuery 工作，但这不符合我的要求。

有人可以帮我解决这个问题吗？

Answer 1

如果只想搜索key-value，可以很简单

//the index
public class FlattenIndex: AbstractIndexCreationTask<PortalEntry>
    {
        public class ReduceResult
        {
            public string Key { get; set; }
            public string Value { get; set; }
        }
        public FlattenIndex()
        {
            Map = portalEntries => from portalEntry in portalEntries                                                               
                                   from p in portalEntry.MetadataProperties.Concat(portalEntry.NamedProperties)
                           select new
                           {
                               Key=p.Key,
                               Value=p.Value
                           };
        }
    }

//the query
 using (var session = _docStore.OpenSession())
            {
                var someEntries = session.Query<FlattenIndex.ReduceResult, FlattenIndex>()
                    .Where(x => x.Key == "Language" && x.Value == "English")
                    .As<PortalEntry>()
                    .ToArray();
                if (someEntries!=null)
                    foreach(var entry in someEntries )
                    {
                        Console.WriteLine(entry.Id);
                    }
            }