自己来控制EntityFramework4.1Code-First，强大的EF多种加载方式

1. var ordercOntext= db.OrderContext.Include(o => o.Product); //外键表贪婪一个，延迟一个Category 

2. var ordercOntext= db.OrderContext.Include(o => o.Product).Include(o=>o.Product.Category) //外键表全贪婪

3. var ordercOntext= db.OrderContext;  //外键表全延时

1.半延迟半贪婪  3次数据库查询

执行时间：0.0181664 
解析时间：0.0629575
总时间：0.0811491

SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Product_ID] AS [Product_ID], 
[Extent1].[Name] AS [Name], 
[Extent1].[Address] AS [Address], 
[Extent1].[CreateTime] AS [CreateTime], 
[Extent2].[ID] AS [ID1], 
[Extent2].[Name] AS [Name1], 
[Extent2].[CategoryID] AS [CategoryID], 
[Extent2].[Price] AS [Price]
FROM  [dbo].[Order] AS [Extent1]
INNER JOIN [dbo].[Product] AS [Extent2] ON [Extent1].[Product_ID] = [Extent2].[ID]

exec sp_executesql N'SELECT 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[CategoryName] AS [CategoryName], 
[Extent1].[IsDel] AS [IsDel]
FROM [dbo].[Category] AS [Extent1]
WHERE [Extent1].[CategoryID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=1

exec sp_executesql N'SELECT 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[CategoryName] AS [CategoryName], 
[Extent1].[IsDel] AS [IsDel]
FROM [dbo].[Category] AS [Extent1]
WHERE [Extent1].[CategoryID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=2

2. 全贪婪  1次数据库查询

执行时间：0.0173032 
解析时间：0.0533344
总时间：0.0706627

SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Product_ID] AS [Product_ID], 
[Extent1].[Name] AS [Name], 
[Extent1].[Address] AS [Address], 
[Extent1].[CreateTime] AS [CreateTime], 
[Extent2].[ID] AS [ID1], 
[Extent2].[Name] AS [Name1], 
[Extent2].[CategoryID] AS [CategoryID], 
[Extent2].[Price] AS [Price], 
[Extent4].[CategoryID] AS [CategoryID1], 
[Extent4].[CategoryName] AS [CategoryName], 
[Extent4].[IsDel] AS [IsDel]
FROM    [dbo].[Order] AS [Extent1]
INNER JOIN [dbo].[Product] AS [Extent2] ON [Extent1].[Product_ID] = [Extent2].[ID]
LEFT OUTER JOIN [dbo].[Product] AS [Extent3] ON [Extent1].[Product_ID] = [Extent3].[ID]
LEFT OUTER JOIN [dbo].[Category] AS [Extent4] ON [Extent3].[CategoryID] = [Extent4].[CategoryID]

3.全延迟加载， 延迟2个表 ，5次数据库查询

执行时间：0.0128477 
解析时间：0.0796226
总时间：0.0925025

SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Product_ID] AS [Product_ID], 
[Extent1].[Name] AS [Name], 
[Extent1].[Address] AS [Address], 
[Extent1].[CreateTime] AS [CreateTime]
FROM [dbo].[Order] AS [Extent1]

exec sp_executesql N'SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Name] AS [Name], 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[Price] AS [Price]
FROM [dbo].[Product] AS [Extent1]
WHERE [Extent1].[ID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=1

exec sp_executesql N'SELECT 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[CategoryName] AS [CategoryName], 
[Extent1].[IsDel] AS [IsDel]
FROM [dbo].[Category] AS [Extent1]
WHERE [Extent1].[CategoryID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=1

exec sp_executesql N'SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Name] AS [Name], 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[Price] AS [Price]
FROM [dbo].[Product] AS [Extent1]
WHERE [Extent1].[ID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=2

exec sp_executesql N'SELECT 
[Extent1].[CategoryID] AS [CategoryID], 
[Extent1].[CategoryName] AS [CategoryName], 
[Extent1].[IsDel] AS [IsDel]
FROM [dbo].[Category] AS [Extent1]
WHERE [Extent1].[CategoryID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=2