How To Convert a DBTIMESTAMP into a DATE (241718)

MORE INFORMATION

If You Are Using MFC, Use this Code

#include <oledb.h>

void MFCTestConversion()
{
   DBTIMESTAMP dbTimeStamp;

   dbTimeStamp.year = 1900;
   dbTimeStamp.month = 1;
   dbTimeStamp.day = 1;
   dbTimeStamp.hour = 0;
   dbTimeStamp.minute = 0;
   dbTimeStamp.second = 0;

   COleDateTime d(dbTimeStamp.year, dbTimeStamp.month, dbTimeStamp.day,  
            dbTimeStamp.hour, dbTimeStamp.minute, dbTimeStamp.second);

   COleVariant var = d;
   DATE date = var.date;
}
				

If You Are Not Using MFC, Use this Code

//headers needed
#include <windows.h>
#include <oledb.h>

// One-based array of days in year at month start
int MonthDays[13] =
	{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};

// Modified Helper taken from \MFC\SRC\OLEVAR.CPP, _AfxOleDateFromTm
// This will compile in .c files too
BOOL OleDateFromTm(WORD wYear, WORD wMonth, WORD wDay, 
                   WORD wHour, WORD wMinute, WORD wSecond, DATE *dtDest)
{
   long nDate;
   double dblTime;
   BOOL bLeapYear;
   int nDaysInMonth;

   // Validate year and month (ignore day of week and milliseconds)
   if (wYear > 9999 || wMonth < 1 || wMonth > 12)
      return FALSE;

   //  Check for leap year and set the number of days in the month
   bLeapYear = ((wYear & 3) == 0) && ((wYear % 100) != 0 || (wYear % 400) == 0);

   nDaysInMonth = MonthDays[wMonth] - MonthDays[wMonth-1] +
               ((bLeapYear && wDay == 29 && wMonth == 2) ? 1 : 0);

   // Finish validating the date
   if (wDay < 1 || wDay > nDaysInMonth || wHour > 23 || wMinute > 59 || wSecond > 59)
      return FALSE;

   // Cache the date in days and time in fractional days
   //It is a valid date; make Jan 1, 1AD be 1
   nDate = wYear*365L + wYear/4 - wYear/100 + wYear/400 + MonthDays[wMonth-1] + wDay;

   //  If leap year and it's before March, subtract 1:
   if (wMonth <= 2 && bLeapYear)
      --nDate;

   //  Offset so that 12/30/1899 is 0
   nDate -= 693959L;

   dblTime = (((long)wHour * 3600L) +  // hrs in seconds
              ((long)wMinute * 60L) +  // mins in seconds
              ((long)wSecond)) / 86400L;

   *dtDest = (double) nDate + ((nDate >= 0) ? dblTime : -dblTime);
   return TRUE;
}

void TestConversion()
{
   BOOL bRet;
   DBTIMESTAMP dbTimeStamp;
   DATE d;

   dbTimeStamp.year = 1900;
   dbTimeStamp.month = 1;
   dbTimeStamp.day = 1;
   dbTimeStamp.hour = 0;
   dbTimeStamp.minute = 0;
   dbTimeStamp.second = 0;

   bRet = OleDateFromTm(dbTimeStamp.year, dbTimeStamp.month,  
                        dbTimeStamp.day, dbTimeStamp.hour,  
                        dbTimeStamp.minute, dbTimeStamp.second, &d);
   if (bRet) //succeeded...
   {
      //d should equal 2.00
   }
}