การแก้ไข: การตั้งค่าของแอตทริบิวต์การเชื่อมต่อล้มเหลวเมื่อคุณใช้การเชื่อมต่อร่วมกันสำหรับการเชื่อมต่อ ODBC ของ SQL Server

// ODBCTestCase.cpp : Defines the entry point for the console application.//

#include "stdafx.h"
#include "windows.h"
#include "sqlext.h"
#include "sql.h" 
#include "stdlib.h"

void GetSQLError();
long InitializeEnvironment();
long Connect(BOOL lbUseDSN);
long Disconnect();
int  ExecuteProcedure();

SQLHENV     ghEnvironment = NULL;
SQLHDBC     ghConnection  = NULL;
HSTMT       ghStatement   = NULL;
/**********************************************
 * main
 **********************************************/
int main(int argc, char* argv[])
{
BOOL lbTransaction = TRUE;
BOOL lbUseDSN      = FALSE;
long lValue =0;

if(argc > 1)
{
if(strcmp(argv[1], "DSN") == 0)
lbUseDSN = TRUE;
if(argc > 2)
{
if(strcmp(argv[2], "TRAN") == 0)
lbTransaction = TRUE;
}
}

if(InitializeEnvironment() == 0)
{
for(long llSub = 0; llSub < 2; llSub++)
{
if(Connect(lbUseDSN) == 0)
{

if(lbTransaction)
SQLSetConnectOption(ghConnection, SQL_AUTOCOMMIT, SQL_AUTOCOMMIT_OFF);

//SQLGetConnectAttr(ghConnection,SQL_ATTR_AUTOCOMMIT,&lValue,0,NULL);

ExecuteProcedure();

if(lbTransaction)
{
SQLTransact(ghEnvironment, ghConnection, SQL_COMMIT); 

//If you do not call the following, the problem does not occur:
SQLSetConnectOption(ghConnection, SQL_AUTOCOMMIT, SQL_AUTOCOMMIT_ON);


//If you call the following the problem does not occur:
//SQLSetConnectOption(ghConnection, SQL_AUTOCOMMIT, SQL_AUTOCOMMIT_OFF);
//SQLGetConnectAttr(ghConnection,SQL_ATTR_AUTOCOMMIT,&lValue,0,NULL);
}

Disconnect();
}
}
SQLFreeHandle(SQL_HANDLE_ENV, ghEnvironment);
}

return 0;
}


/**********************************************
 * InitializeEnvironment
 **********************************************/
long InitializeEnvironment()
{
if (!SQL_SUCCEEDED(SQLSetEnvAttr(NULL,
 SQL_ATTR_CONNECTION_POOLING,
 (SQLPOINTER)SQL_CP_ONE_PER_DRIVER,
 SQL_IS_INTEGER)))
{
GetSQLError();
return 8;
}

if(!SQL_SUCCEEDED(SQLAllocHandle(SQL_HANDLE_ENV, NULL, &ghEnvironment)))
{
GetSQLError();
return 8;
}
if(!SQL_SUCCEEDED(SQLSetEnvAttr(ghEnvironment, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC2, SQL_IS_INTEGER)))
{
GetSQLError();
return 8;
}
if (!SQL_SUCCEEDED(SQLSetEnvAttr(ghEnvironment, 
 SQL_ATTR_CP_MATCH,
 (SQLPOINTER) SQL_CP_STRICT_MATCH , 
 //(SQLPOINTER) SQL_CP_RELAXED_MATCH , 
 SQL_IS_INTEGER)))
{
GetSQLError();
return 8;
}

return 0;   
}
/**********************************************
 * Connect
 **********************************************/
long Connect(BOOL lbUseDSN)
{
SQLCHAR     lszOutConnectString[1024];
SQLSMALLINT llReturnLength;
SQLAllocHandle(SQL_HANDLE_DBC, ghEnvironment, &ghConnection);

//  If you set the isolation before opening the connection, no error reported.
//  Customer cannot set this attribute before opening connection because the object 
//is running under COM+, and under COM+ isolation levels automatically are set to serializable
//if(!SQL_SUCCEEDED(::SQLSetConnectAttr(ghConnection, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)SQL_TXN_READ_COMMITTED , SQL_IS_INTEGER)))
//{
// GetSQLError();
//  return 8;
//}

if(lbUseDSN)
{
int iReturn = ::SQLConnect(ghConnection,
   (SQLCHAR*)"LocalCPR",
   SQL_NTS,
   (SQLCHAR*)"sa",
   SQL_NTS,
   (SQLCHAR*)"password1",
   SQL_NTS);
if(!SQL_SUCCEEDED(iReturn))
{
GetSQLError();
return 8;
}
}
else
{
if(!SQL_SUCCEEDED(SQLDriverConnect(ghConnection, 
   NULL,
   (SQLCHAR*)"DSN=LocalCPR;UID=sa;PWD=password1;",
   SQL_NTS,
   lszOutConnectString,
   1024,
   &llReturnLength,
   SQL_DRIVER_NOPROMPT)))
{
GetSQLError();
return 8;
}
}

SQLAllocStmt(ghConnection, &ghStatement);

//If you set the isolation after you open the connection, you see the problem.
if(!SQL_SUCCEEDED(::SQLSetConnectAttr(ghConnection, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)SQL_TXN_READ_COMMITTED , SQL_IS_INTEGER)))
{
 GetSQLError();
  return 8;
}
return 0;
}
/**********************************************
 * Disconnect
 **********************************************/
long Disconnect()
{
if(ghStatement)
{
if(!SQL_SUCCEEDED(SQLFreeHandle(SQL_HANDLE_STMT, ghStatement)))
{
GetSQLError();
return 8;
}
ghStatement = NULL;
}

if(ghConnection)
{
::SQLDisconnect(ghConnection);

if(!SQL_SUCCEEDED(SQLFreeHandle(SQL_HANDLE_DBC, ghConnection)))
{
GetSQLError();
return 8;
}
ghConnection = NULL;
}
return 0;
}
/**********************************************
 * ExecuteProcedure
 **********************************************/
int ExecuteProcedure()
{
SQLINTEGER  mlIndicator = 0; 
SQLRETURN   lnSqlRetCd = SQL_SUCCESS; 
::SQLFreeStmt(ghStatement, SQL_CLOSE);
::SQLFreeStmt(ghStatement, SQL_UNBIND);

/*****************************************************************/
/* Execute Procedure
/*****************************************************************/
RETCODE llDbRetCd = SQLExecDirect(ghStatement, (SQLCHAR*)"SELECT * From Table1", SQL_NTS);
if((llDbRetCd != SQL_SUCCESS) && (llDbRetCd != SQL_SUCCESS_WITH_INFO))
{
GetSQLError();
return 8;
}


/*****************************************************************/
/* Bind return Value
/*****************************************************************/
char lszReturnBuf[300];
SDWORD lSts;

llDbRetCd = SQLBindCol(ghStatement, 1, SQL_C_TCHAR, &lszReturnBuf, 300, &lSts);

if ((llDbRetCd != SQL_SUCCESS) && (llDbRetCd != SQL_SUCCESS_WITH_INFO))
{
GetSQLError();
return 8;
}


/*****************************************************************/
/* Fetch Result
/*****************************************************************/
llDbRetCd = SQLFetch(ghStatement);
if ((llDbRetCd != SQL_SUCCESS) && (llDbRetCd != SQL_SUCCESS_WITH_INFO))
{
GetSQLError();
return 8;
}

printf("Output Value : %s\n",lszReturnBuf);
return 0;
}

/**********************************************
 * GetSQLError
 **********************************************/
void GetSQLError()
{
long    llDbErrCd = 0;
short   llRetMsgLen = 0;
char    lszSqlErrMsg[255];
char    lszSqlMsg[255];

   SQLError(ghEnvironment,
            ghConnection,
            ghStatement,
            (SQLCHAR*) lszSqlErrMsg,
            &llDbErrCd,
            (SQLCHAR*) lszSqlMsg,
            255,
            &llRetMsgLen);
printf(lszSqlErrMsg);
printf(lszSqlMsg);
}