Question

我正在尝试将Ayende的订单搜索从here应用到现有索引。

目前的指数如下：

public class HomeBlurb_IncludeTotalCosts_Search2 : AbstractIndexCreationTask<MPDocument, HomeBlurb_IncludeTotalCosts_Search2.ReduceResult>
{
    public class ReduceResult
    {
        public string Name { get; set; }
        public string Constituency { get; set; }
        public decimal? AmountPaid { get; set; }
    }

    public HomeBlurb_IncludeTotalCosts_Search2()
    {
        Map = mps => from mp in mps
                        from exp in mp.Expenses
                        select new
                        {
                            mp.Name,
                            mp.Constituency,
                            exp.AmountPaid
                        };

        Reduce = results => from result in results
                            group result by new { result.Name, result.Constituency } into g
                            select new
                            {
                                Name = g.Key.Name,
                                Constituency = g.Key.Constituency,
                                AmountPaid = g.Sum(x => x.AmountPaid)
                            };

        Index(x => x.Name, FieldIndexing.Analyzed);
        Index(x => x.Constituency, FieldIndexing.Analyzed);
    }
}

此索引运行正常。但是当我尝试将Map更改为：

时

from mp in mps
from exp in mp.Expenses
select new
{
    Query = new object[]{mp.Name,mp.Constituency},
    mp.Name,
    mp.Constituency,
    exp.AmountPaid
};

和reduce to

from result in results
group result by new { result.Name, result.Constituency } into g
select new
{
    Query = "",
    Name = g.Key.Name,
    Constituency = g.Key.Constituency,
    AmountPaid = g.Sum(x => x.AmountPaid)
};

在查询Query属性时，我得不到任何结果。如果我删除了reduce，则索引返回数据，但它总是返回完整的MPDocument，这比我实现的要多得多。有没有办法使用原始帖子中描述的技术，也使用减少？

Answer 1

您可以在reduce函数中使用它：

Query = g.Select(x => x.Query).Where(x => x != null).FirstOrDefault()

要查询该字段，您需要具有单独的查询模型和结果模型。以下是使用您的代码的完整示例：

public class MultiTermFieldInMapReduce
{
    public class MPDocument
    {
        public List<Epense> Expenses { get; set; }
        public string Name { get; set; }
        public string Constituency { get; set; }

        public class Epense
        {
            public decimal? AmountPaid { get; set; }
        }
    }

    public class HomeBlurb_IncludeTotalCosts_Search2 : AbstractIndexCreationTask<MPDocument, HomeBlurb_IncludeTotalCosts_Search2.ReduceResult>
    {
        public class ReduceResult
        {
            public string Name { get; set; }
            public string Constituency { get; set; }
            public decimal? AmountPaid { get; set; }
            public object[] Query { get; set; }
        }

        public class SearchModel
        {
            public string Name { get; set; }
            public string Constituency { get; set; }
            public decimal? AmountPaid { get; set; }
            public string Query { get; set; }
        }

        public HomeBlurb_IncludeTotalCosts_Search2()
        {
            Map = mps => from mp in mps
                         from exp in mp.Expenses
                         select new
                         {
                             mp.Name,
                             mp.Constituency,
                             exp.AmountPaid,
                             Query = new object[]
                             {
                                 mp.Name,
                                 mp.Constituency
                             }
                         };

            Reduce = results => from result in results
                                group result by new { result.Name, result.Constituency } into g
                                select new
                                {
                                    Name = g.Key.Name,
                                    Constituency = g.Key.Constituency,
                                    AmountPaid = g.Sum(x => x.AmountPaid),
                                    Query = g.Select(x => x.Query).Where(x => x != null).FirstOrDefault()
                                };

            Index(x => x.Name, FieldIndexing.Analyzed);
            Index(x => x.Constituency, FieldIndexing.Analyzed);
        }
    }

    [Fact]
    public void Query_returns_results()
    {
        using (var store = new EmbeddableDocumentStore { RunInMemory = true }.Initialize())
        {
            using (var session = store.OpenSession())
            {
                session.Store(new MapReduceError.MPDocument
                {
                    Name = "test1",
                    Expenses = new List<MapReduceError.MPDocument.Epense>
                    {
                        new MapReduceError.MPDocument.Epense {AmountPaid = 5.5m},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 5.5m},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 5.5m},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 5.5m}
                    }
                });

                session.Store(new MapReduceError.MPDocument
                {
                    Name = "test2",
                    Expenses = new List<MapReduceError.MPDocument.Epense>
                    {
                        new MapReduceError.MPDocument.Epense {AmountPaid = 10},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 10},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 10},
                        new MapReduceError.MPDocument.Epense {AmountPaid = 10}
                    }
                });

                session.SaveChanges();
            }

            new HomeBlurb_IncludeTotalCosts_Search2().Execute(store);

            using (var session = store.OpenSession())
            {
                var results =
                    session.Query
                        <HomeBlurb_IncludeTotalCosts_Search2.SearchModel, HomeBlurb_IncludeTotalCosts_Search2>()
                        .Customize(x => x.WaitForNonStaleResultsAsOfLastWrite())
                        .Where(x => x.Query == "test1")
                        .As<HomeBlurb_IncludeTotalCosts_Search2.ReduceResult>()
                        .ToList();

                Assert.Equal(1, results.Count);
                Assert.Equal(22, results.First().AmountPaid);
            }
        }

    }
}

Answer 2

我认为你不需要Map / Reduce索引才能做到这一点，你似乎只是减少了MPDocument名称和选区，我认为每个MP都是独一无二的。

我认为您想要使用TransformResults，以便您可以改变输出的形状，如下所示：

 TransformResults =
            (database, mps) => from mp in mps
                                 select new 
                                 {
                                     mp.Name,
                                     mp.???
                                     < JUST THE BITS YOU WANT RETURNED >
                                 };

然后你这样查询：

session.Query<mp>("index name")
        .Where(..)
        .As<MPQueryResult>()
        .ToList()

RavenDB索引不再返回结果

2 个答案: