Question

我有一个包含中央表的数据库，其中有超过30个表由FK引用。一个条目在主表中总是有一行，并且根据信息的类型，可能是1或2（我目前无法想到它在2个以上的任何场景）的关联表。 / p>

根据客户的不同，只有正在填充的表会显示给最终用户，他们可以动态选择将哪些信息列返回给他们。

我正在使用Entity Framework来访问记录，并且发现了所有引用表的速度困境。如果我只是做一些事情：

var v = from r in context.Records
select r;

当它执行查询时，它还会为每个关联的表执行子查询，无论它是否有条目。当在一个状态良好的本地局域网上，它速度快，但有明显的延迟。远程运行这些查询时，每条记录大部分时间都需要运行所有相关查询。相关查询的示例位于此帖的底部。我创建了一个实体模型，它只有一些表而不是用于演示目的的完整集，并从EF获得了日志输出。我只粘贴了1个记录查询集的输出。

因此，我的想法是使用linq将

的内容放在一起

var v = from r in context.Records
        select new { ID = r.ID, val1 = r.val1, val2=r.val2, val3 = r.child_table1.val1, r.child_table1.val2 };

就删除不需要的查询的开销和删除性能问题而言，这完全符合我的要求....（这是我目前卡住的地方）。

但是，child_table和列名称是必须是动态的部分。我将始终拉出主表的列，但我需要动态创建与相关表中的列相关的选择部分。

例如，客户可能只有3个正在填充的子表，因此不需要其余的子表。但是，由于我们在世界各地拥有众多客户，所以每个人都不同，所以编写每个可能的场景都是不切实际的，也不可维护，因为我们总是需要处理新事物来更新/添加。

因此，对于我的正常情况，我需要2-4个子表，以及每个子表的所有列。我可以管理从ui呈现的列。最大的挑战是只查询实际上有行的子表。

希望我过度思考这个，有人会给我一个时刻。

非常感谢任何想法或提示。

由于

    SELECT 
    [GroupBy1].[A1] AS [C1]
    FROM ( SELECT 
        COUNT(1) AS [A1]
        FROM [dbo].[records] AS [Extent1]
    )  AS [GroupBy1]
-- Executing at 11/29/2013 9:03:02 PM -05:00
-- Completed in 20 ms with result: SqlDataReader

SELECT TOP (128) 
    [Extent1].[ID] AS [ID], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[records] AS [Extent1]
    ORDER BY [Extent1].[ID] ASC
-- Executing at 11/29/2013 9:03:02 PM -05:00
-- Completed in 67 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---] AS [Extent1]
    WHERE [Extent1].[RecordID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 25 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
        [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---2] AS [Extent1]
    WHERE [Extent1].[ID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 20 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
        [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---3] AS [Extent1]
    WHERE [Extent1].[ID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 18 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---4] AS [Extent1]
    WHERE [Extent1].[ID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 30 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---5] AS [Extent1]
    WHERE [Extent1].[ID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 23 ms with result: SqlDataReader

SELECT 
    [Extent1].[ID] AS [ID], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---], 
    [Extent1].[---] AS [---]
    FROM [dbo].[meta_---6] AS [Extent1]
    WHERE [Extent1].[ID] = @EntityKeyValue1
-- EntityKeyValue1: '1' (Type = Int64)
-- Executing at 11/29/2013 9:03:03 PM -05:00
-- Completed in 18 ms with result: SqlDataReader

动态LINQ从关系表中选择

0 个答案: