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我是EF新手,所以忍耐一下:○EF - 问题在一对多选择查询生成
我在DB一个非常简单的关系。 ts_Order表{ID,OrderDate,OrderNumber}和ts_OrderDetails表{ID,ProductId,OrderID}。两个表中的ID都是PK和标识列。 ts_OrderDetails表中的OrderID是FK,并引用ts_Order表的ID列。
我需要选择所有订单以及每个订单可能具有的每个细节。在SQL我会写这样的事情:
select * from ts_Order ORD inner join ts_OrderDetails DTL on ORD.ID=DTL.OrderID
这工作得很好。
当我尝试做的EF类似的东西:
List<Order> result = context.Orders.Include("OrderDetails").Where(i => i.ID > 0).ToList();
这是由EF生成的内容:
SELECT
[Project1].[ID] AS [ID],
[Project1].[OrderDate] AS [OrderDate],
[Project1].[OrderNumber] AS [OrderNumber],
[Project1].[C1] AS [C1],
[Project1].[ID1] AS [ID1],
[Project1].[Product] AS [Product],
[Project1].[OrderID] AS [OrderID]
FROM (SELECT
[Extent1].[ID] AS [ID],
[Extent1].[OrderDate] AS [OrderDate],
[Extent1].[OrderNumber] AS [OrderNumber],
[Extent2].[ID] AS [ID1],
[Extent2].[Product] AS [Product],
[Extent2].[OrderID] AS [OrderID],
CASE WHEN ([Extent2].[ID] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C1]
FROM [dbo].[ts_Order] AS [Extent1]
LEFT OUTER JOIN (SELECT
[ts_OrderDetails].[ID] AS [ID],
[ts_OrderDetails].[Product] AS [Product],
[ts_OrderDetails].[OrderID] AS [OrderID]
FROM [dbo].[ts_OrderDetails] AS [ts_OrderDetails]) AS [Extent2] ON [Extent1].[ID] = [Extent2].[OrderID]
WHERE [Extent1].[ID] > 0
) AS [Project1]
ORDER BY [Project1].[ID] ASC, [Project1].[C1] ASC
为什么会产生如此复杂的查询?我错过了什么吗?
-Vinod
只要是EF如何工作的。 –
Linq2Sql会做出什么样的查询,更好还是更差? – Magnus
我从来没有使用过LINQ to SQL。可能是我应该尝试一下!我会让你知道它出现了什么。 – Vinod