我正在尝试从用c ++编写的控制台应用程序调用我的Microsoft SQL服务器上的用户定义函数。我使用ADO来完成整个事情。
我的功能看起来像这样(当我在管理工作室使用它时它可以工作)
CREATE FUNCTION [dbo].[funcHowOftenDidHeWin]
(
@playername as varchar(15)
@percentWon float OUTPUT
)
RETURNS float
AS
BEGIN
DECLARE @wintimes float
DECLARE @participated float
DECLARE @percentWon float
SELECT @wintimes = COUNT(DidWin)
FROM PPLP0p02
WHERE DidWin = 1 AND Playername=@playername
SELECT @participated = COUNT(DidWin)
FROM PPLP0p02
WHERE Playername = @playername
IF @wintimes >0
SET @percentWon = @wintimes / @participated *100
IF @wintimes = 0
SET @percentWon = 0
RETURN @percentWon
END
GO
从我的程序中,我尝试按如下方式调用它:
USEADO::_ConnectionPtr connection;
USEADO::_RecordsetPtr recordset; //create a "
if(FAILED(hr = CoInitialize(NULL))) //
{ return hr;}
if(FAILED(hr = connection.CreateInstance(__uuidof(USEADO::Connection))))
{ return hr;}
if(FAILED(hr = recordset.CreateInstance(__uuidof(USEADO::Recordset))))
{ return hr;}
connection->CursorLocation = USEADO::adUseServer;
try
{
connection->Open(L"Provider=SQLOLEDB.1;Persist Security Info=False;User ID=Test;Initial Catalog=Haufen;Data Source=Wolle\\SQLEXPRESS", L"Test", L"Test", USEADO::adConnectUnspecified);
}
catch(...) {std::cout << "!!! connection->Open(ConnectionString FAILED !!!" << std::endl; }
//This works
recordset->Open("SELECT playername FROM Summary WHERE playersatbegin=5",connection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
//This not
recordset->Open("SELECT dbo.funcHowOftenDidHeWin('Lumpi') ",connection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
嗯,它不起作用。调试器在第1580行的masado15.tli中结束,VS显示一个错误的窗口:35h.exe中0x7c812afb处的未处理异常:Microsoft C ++异常:内存位置为0x0012c3f8的_com_error。
我不确定语法是否正确,我想知道服务器应该知道哪个表我想要结果....
那里有任何帮助吗?感谢
Lumpi
答案 0 :(得分:0)
您可以将该函数重写为存储过程。 FLOAT可以作为RETURN值或OUT参数返回。