How NOCOUNT affects ADO.NET一文中提到：

Previously, in Classic ASP and ADO, NOCOUNT was most commonly a factor if you were checking RecordsAffected on Command.Execute(). SqlDataReader does have a RecordsAffected property, but it's rarely used since it's not populated until the datareader has iterated all the rows and the datareader is closed. There are some possible implications if you're using DataAdapters to submit changes to the database, since it uses the rows affected result to determine if the update succeeded. Probably the easiest way to check for that case is to search the codebase for SqlDataAdapter and see if the Update() method is being called.

還有：

Tech notes if you're interested in tracing how RecordsAffected is set and used by pointing Reflector at System.Data:
System.Data.SqlClient.TdsParser.ProcessDone() sets RecordsAffected.
System.Data.Common.DbDataAdapter.UpdateRow() uses reader.RecordsAffected in determining whether to call AcceptChanges and ApplyToDataRow.

保險一點來說，通過作者所說的調(diào)用Update()來做判斷似乎并不可靠，中間有很多步驟都有可能出問題從而影響最終的結(jié)果。同時，debug起來的也有麻煩了，嵌入sql debug后對于調(diào)試程序很有用，而如果按作者所說這個debug的功能都被削減了。又把database和application給分開調(diào)了。

評論中有人寫了一個簡單的測試程序，并給出了他的測試結(jié)果，他認(rèn)為還是SET NOCOUNT ON快。

測試使用的存儲過程
DECLARE?@Start?DATETIME,?@End?DATETIME,?@Counter?INT,?@NoCountOff?INT,?@NoCountOn?INT

CREATE?TABLE?#MyTable?(

Id?INT?NOT?NULL?IDENTITY(1,1)?PRIMARY?KEY

,?FirstName?VARCHAR(128)?NOT?NULL

,?LastName?VARCHAR(128)?NOT?NULL

)

SET?NOCOUNT?OFF

SET?@Counter?=?1

SET?@Start?=?GETDATE()

WHILE?@Counter?<=?150000

BEGIN

INSERT?#MyTable?(FirstName,?LastName)?VALUES?('Scott',?'Whigham')

SET?@Counter?=?@Counter?+?1

END

SET?@End?=?GETDATE()

SELECT?@NoCountOff?=?DATEDIFF(ms,?@Start,?@End)

SET?NOCOUNT?ON

SET?@Counter?=?1

SET?@Start?=?GETDATE()

WHILE?@Counter?<=?150000

BEGIN

INSERT?#MyTable?(FirstName,?LastName)?VALUES?('Scott',?'Whigham')

SET?@Counter?=?@Counter?+?1

END

SET?@End?=?GETDATE()

SELECT?@NoCountOn?=?DATEDIFF(ms,?@Start,?@End)

SELECT?@NoCountOff?AS?'NoCountOff',?@NoCountOn?AS?'NoCountOn',?COUNT(*)?AS?NumberOfRows?FROM?#MyTable

DROP?TABLE?#MyTable

我與他測試的環(huán)境不同，在xp + SQL 2005 Ent with SP1上測試的，結(jié)果結(jié)論相反，把結(jié)果數(shù)據(jù)也share給大家：

NoCountOff?? |?? NoCountOn?|?xRate

7106????5893????20.58%
6156????6890????-10.61%
7093????7343????-3.41%
5780????6406????-9.77%
5563????6860????-18.91%
5610????7390????-24.09%
5810????6923????-21.38%
6296????7436????-15.33%

-- insert 1
46????0
16????0
0????0
0????0
16????0

-- insert 1000
420?????393?????6.88%
423?????390?????8.47%
966?????423?????128.37%

-- insert 100,000
43250????42860????0.91%

-- delete all then insert 100,000
42076????39826????5.65%

如果您也親自測試一下可以很明顯的發(fā)現(xiàn)：結(jié)果對于證明起到的作用很小。

與50位技術(shù)專家面對面20年技術(shù)見證，附贈技術(shù)全景圖

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