您可以使用 MultiMap/Reduce 索引来实现此目的,但您需要一些技巧:
1)您需要减少使用字符串,而不是指南。您仍然可以在 AB 类中获取这些值作为指导,正如我将在下面演示的那样。
2)你不能将AB类的第一个属性称为“Id”,因为raven会尝试将其翻译为“__document_id”。所以称之为“AId”,它会工作得很好。
3)在映射阶段,您必须自己操作字符串以去除文档键前缀。
这是一个将所有内容组合在一起的示例程序。这表明它确实有效,但我认为这也说明了为什么 Ayende 更喜欢字符串标识符,这样您就不必处理这种混乱。
using System;
using System.Linq;
using Raven.Client.Document;
using Raven.Client.Indexes;
namespace RavenScratchTest
{
class Program
{
static void Main()
{
var documentStore = new DocumentStore { Url = "http://localhost:8080" };
documentStore.Initialize();
IndexCreation.CreateIndexes(typeof(Program).Assembly, documentStore);
using (var session = documentStore.OpenSession())
{
var b = new B { Id = Guid.NewGuid(), Name = "Foo" };
var a = new A { Id = Guid.NewGuid(), BId = b.Id };
session.Store(a);
session.Store(b);
session.SaveChanges();
}
using (var session = documentStore.OpenSession())
{
var a = session.Query<A>().Customize(x => x.WaitForNonStaleResults()).First();
var b = session.Query<B>().Customize(x => x.WaitForNonStaleResults()).First();
Console.WriteLine("A: Id = {0}", a.Id);
Console.WriteLine(" BId = {0}", a.BId);
Console.WriteLine();
Console.WriteLine("B: Id = {0}", b.Id);
Console.WriteLine(" Name = {0}", b.Name);
Console.WriteLine();
var guid = a.Id;
var ab = session.Query<AB, MyIndex>().Customize(x => x.WaitForNonStaleResults())
.FirstOrDefault(t => t.AId == guid);
if (ab == null)
Console.WriteLine("AB: NULL");
else
{
Console.WriteLine("AB: AId = {0}", ab.AId);
Console.WriteLine(" BId = {0}", ab.BId);
Console.WriteLine(" BName = {0}", ab.BName);
Console.WriteLine();
}
}
Console.WriteLine();
Console.WriteLine("Done.");
Console.ReadLine();
}
}
class A
{
public Guid Id { get; set; }
public Guid BId { get; set; }
}
class B
{
public Guid Id { get; set; }
public string Name { get; set; }
}
class AB
{
public Guid AId { get; set; }
public Guid BId { get; set; }
public string BName { get; set; }
}
class MyIndex : AbstractMultiMapIndexCreationTask<MyIndex.ReduceResult>
{
public MyIndex()
{
AddMap<A>(docs => from a in docs
select new
{
AId = a.Id.ToString().Split('/')[1],
a.BId,
BName = (string)null
});
AddMap<B>(docs => from b in docs
select new
{
AId = (string)null,
BId = b.Id.ToString().Split('/')[1],
BName = b.Name
});
Reduce = results => from result in results
group result by result.BId
into g
select new
{
g.FirstOrDefault(x => x.AId != null).AId,
BId = g.Key,
g.FirstOrDefault(x => x.BName != null).BName
};
}
internal class ReduceResult
{
public string AId { get; set; }
public string BId { get; set; }
public string BName { get; set; }
}
}
}