3
我6碼第一次使用實體框架和我有一個簡單的模型:我可以避免實體框架使用SQL_VARIANT進行查詢嗎?
public class Task
{
[Key]
public int aid {get;set;}
[MaxLength(256)]
public string Memo {get;set;}
}
我也得到一個模型:
int id = 3;
from t in db.Tasks
where t.aid == id
select t;
或
int id = 3;
db.Tasks.Find(id);
它肯定是快,但不......
我查看EF ORM生成的IntelliTrace中的SQL,就像這樣:
DECLARE @p__linq__0 AS SQL_VARIANT;
SET @p__linq__0 = 3;
SET STATISTICS TIME ON
SET STATISTICS IO ON
SELECT
[Limit1].[aid] AS [aid],
[Limit1].[Memo] AS [Memo]
FROM (SELECT TOP (1)
[Extent1].[aid] AS [aid],
[Extent1].[Memo] AS [Memo]
FROM [dbo].[Task] AS [Extent1]
WHERE [Extent1].[aid] = @p__linq__0
) AS [Limit1]
SET STATISTICS TIME OFF
SET STATISTICS IO OFF
我添加SET STATISTICS並在SSMS中測試它。
表'任務'。 掃描計數1,...
它使用SQL_VARIANT!執行計劃是掃描表,而不是聚集尋求!
爲什麼EF做到這一點?我可以避免它嗎?
(LocalDB with SQL Server 2012)
什麼是任務表定義(至少[aid]列定義)? – 2014-09-05 15:14:27
[aid]是int集羣主鍵。 – litfal 2014-09-05 16:06:41