bdedatabase.cpp

程序1

	}

	// allocate memory for the string buffer to recieve data
	pBYTE pDestBuf = (pBYTE)malloc(nSize*sizeof BYTE);
	memset(pDestBuf, 0, nSize*sizeof BYTE);


	if (pDestBuf == NULL)
	{
		// Throw memory exception here
		free(pRecBuf);
		strError.Format("Failed to get record information.");
		throw new CBdeException(DBIERR_NOMEMORY, m_szTableName, m_szDatabaseName, strError);
		return dtRetVal;
	}
	
	// get the actual field value

	switch (nFieldType)
	{
		case fldDATE:
		{
			dbiResult = DbiGetField(m_hCursor, nFieldNumber, pRecBuf, 
				(pBYTE)pDestBuf, pbBlank);
			if (*pbBlank == FALSE)
			{
				// Here is a difficult situation...
				// dates are returned as 4 bytes, but in the 32-bit world
				// the DATE type is 8 bytes.  Typcasting directly to DATE
				// does not work.  We have to type cast to 32 bit int, then
				// to 64-bit int, and then to DATE
				INT32 n32 = (*(INT32 *)pDestBuf);
				dtRetVal = DateToOleDateTime(n32);
			}
			break;
		}
		case fldTIME:
		{
			dbiResult = DbiGetField(m_hCursor, nFieldNumber, pRecBuf, 
				(pBYTE)pDestBuf, pbBlank);
			if (*pbBlank == FALSE)
			{
				dtRetVal = TimeToOleDateTime((*(TIME *)pDestBuf));
			}
			break;
		}
		case fldTIMESTAMP:
		{
			// sie of timestamp is 8
			dbiResult = DbiGetField(m_hCursor, nFieldNumber, pRecBuf, 
				(pBYTE)pDestBuf, pbBlank);
			if (*pbBlank == FALSE)
			{
				TIMESTAMP timestamp = *(TIMESTAMP*)pDestBuf;
				dtRetVal = TimeStampToOleDateTime(timestamp);
			}
			break;
		}
		default:
		{
			nBdeExError = BDEEXERR_FIELDNOTDATE;
		}
	} // end of swtich

	if (dbiResult != DBIERR_NONE || nBdeExError != 0)
	{
		// Throw exception here
		strError.Format("Failed to retrieve data for field %d.",
			nFieldNumber);
	  free(pRecBuf);
		free(pDestBuf);
		throw new CBdeException(dbiResult, nBdeExError, m_szTableName, 
			m_szDatabaseName, strError);
		return dtRetVal;
	} 

	free(pDestBuf);
  free(pRecBuf);
	return dtRetVal;
} // end of GetFieldAsDate





// function to get the field value as an integer
// throws an exception for incompatible data types
BOOL CBdeDatabase::GetFieldAsBoolean(UINT16 nFieldNumber, BOOL* pbBlank)
{
	// Throw an exception if database is in Edit mode
	if (!CheckValidCursor("Failed to get field value.")) return 0L;
	if (!CheckNotEditMode("Failed to get field value.")) return 0L;

	DBIResult dbiResult = DBIERR_NONE;
	BOOL bValue = FALSE;
	CString strError;
  CURProps curProps; // Table Properties
	pFLDDesc pFldDesc; // field information
  pBYTE pRecBuf; // Record Buffer
	int nBdeExError = 0;

	
	// get the cursor properties for the table
  dbiResult = DbiGetCursorProps(m_hCursor, &curProps);
	if (dbiResult != DBIERR_NONE)
  {
		strError.Format("Failed to get cursor properties.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return FALSE;
  }

	// make sure the field number is valid
	// TODO:  This should throw an exception
	if (nFieldNumber < 1 || nFieldNumber > curProps.iFields)
	{
		strError.Format("Invalid field index %d.  Valid numbers are between 1 and %d.", 
			nFieldNumber, curProps.iFields);
		throw new CBdeException(DBIERR_NONE, BDEEXERR_INVALIDFIELDINDEX,
			m_szTableName, m_szDatabaseName, strError);
		return FALSE;
	}


	// allocate memory for the field descriptors
	pFldDesc = (pFLDDesc)malloc(curProps.iFields * sizeof(FLDDesc));
	if (pFldDesc == NULL)
	{
		// Throw exception for DBIERR_NOMEMORY
		throw new CBdeException(DBIERR_NOMEMORY);
		return FALSE;
	}

	dbiResult = DbiGetFieldDescs(m_hCursor, pFldDesc);
	if (dbiResult != DBIERR_NONE)
	{
		free(pFldDesc);
		strError.Format("Failed to retrieve field information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return FALSE;
	}

		
	// save the size and type of the field
	UINT16 nSize = pFldDesc[nFieldNumber-1].iLen;
	UINT16 nFieldType = pFldDesc[nFieldNumber-1].iFldType;

	free(pFldDesc); // clean up the field descriptor
	pFldDesc = NULL;


	// allocate the record buffer for the table
  pRecBuf = (pBYTE) malloc(curProps.iRecBufSize * sizeof(BYTE));
	if (pRecBuf == NULL)
  {
		strError.Format("Insufficient memory to get field number %d.", nFieldNumber);
		throw new CBdeException(DBIERR_NOMEMORY, m_szTableName, m_szDatabaseName, strError);
    return FALSE;
  }

	// fill the record buffer with information
	dbiResult = DbiGetRecord(m_hCursor, dbiNOLOCK, pRecBuf, NULL);
	if (dbiResult != DBIERR_NONE)
	{
		free(pRecBuf);
		strError.Format("Failed to get record information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
	  return FALSE;
	}

	// allocate memory for the string buffer to recieve data
	pBYTE pDestBuf = (pBYTE)malloc(nSize*sizeof BYTE);
	memset(pDestBuf, 0, nSize*sizeof BYTE);


	if (pDestBuf == NULL)
	{
		// Throw memory exception here
		free(pRecBuf);
		strError.Format("Failed to get record information.");
		throw new CBdeException(DBIERR_NOMEMORY, m_szTableName, m_szDatabaseName, strError);
		return FALSE;
	}
	
	// get the actual field value

	switch (nFieldType)
	{
		case fldBOOL:
		{
			dbiResult = DbiGetField(m_hCursor, nFieldNumber, pRecBuf, (pBYTE)pDestBuf, pbBlank);
			if (*pbBlank == FALSE)
      {
        if (*(BYTE*)pDestBuf == 0) bValue = FALSE;
        else bValue = TRUE;
      }
			break;
		}
		default:
		{
			nBdeExError = BDEEXERR_FIELDNOTINTEGER;
		}
	} // end of swtich

	// process the final exceptions
	if (dbiResult != DBIERR_NONE || nBdeExError != 0)
	{
		// Throw exception here
		strError.Format("Failed to retrieve data for field %d.",
			nFieldNumber);
	  free(pRecBuf);
		free(pDestBuf);
		throw new CBdeException(dbiResult, nBdeExError, m_szTableName, 
			m_szDatabaseName, strError);
		return FALSE;
	} 

	free(pDestBuf);
  free(pRecBuf);
	return bValue;
} // end of GetFieldAsBoolean




// returns the 1 based index of a field name
// returns 0 on error
int CBdeDatabase::GetFieldSize(int nFieldNumber)
{
	// Throw an exception if not in edit mode
	if (!CheckValidCursor("Failed to get field size.")) return 0;

	DBIResult dbiResult;
	CURProps CurProps;
	pFLDDesc pFldDesc;
	int nSize = -1;
	CString strError;

	dbiResult = DbiGetCursorProps(m_hCursor, &CurProps);

	if (dbiResult != DBIERR_NONE)
	{
		strError.Format("Failed to retrieve size of field %d.",
			nFieldNumber);
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return -1;
	}


	pFldDesc = (pFLDDesc)malloc(CurProps.iFields * sizeof(FLDDesc));
	if (pFldDesc == NULL)
	{
		// Throw exception for DBIERR_NOMEMORY
		throw new CBdeException(DBIERR_NOMEMORY);
		return -1;
	}

	dbiResult = DbiGetFieldDescs(m_hCursor, pFldDesc);

	if (dbiResult != DBIERR_NONE)
	{
		free(pFldDesc);
		strError.Format("Failed to retrieve field information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return -1;
	}
		
	nSize = pFldDesc[nFieldNumber-1].iLen;
	free(pFldDesc);
	return nSize;
}
	

// returns the number of fields in the current table
// returns -1 on error
int CBdeDatabase::GetFieldCount()
{
	if (!CheckValidCursor("Failed to get field count.")) return -1;

	DBIResult dbiResult;
	CURProps CurProps;
	CString strError;
	CString strRetVal;

	dbiResult = DbiGetCursorProps(m_hCursor, &CurProps);

	if (dbiResult != DBIERR_NONE)
	{
		strError.Format("Failed to cursor properties in table %s.",
			m_szTableName);
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return 0;
	}

	return CurProps.iFields;
}


// function to get the filed type
// returns 0 on error
int CBdeDatabase::GetFieldType(int nFieldNumber)
{
	// Throw an exception if not in edit mode
	if (!CheckValidCursor("Failed to get field type.")) return FALSE;
	if (!CheckEditMode("Failed to get field type.")) return FALSE;

	DBIResult dbiResult;
  CURProps curProps; // Table Properties
	pFLDDesc pFldDesc; // field information
	CString strError;

	// get the cursor properties for the table
  dbiResult = DbiGetCursorProps(m_hCursor, &curProps);
	if (dbiResult != DBIERR_NONE)
  {
		strError.Format("Failed to get cursor properties.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return 0;
  }

	// make sure the field number is valid
	if (nFieldNumber < 1 || nFieldNumber > curProps.iFields)
	{
		strError.Format("Invalid field index %d.  Valid numbers are between 1 and %d.", 
			nFieldNumber, curProps.iFields);
		throw new CBdeException(DBIERR_NONE, BDEEXERR_INVALIDFIELDINDEX,
			m_szTableName, m_szDatabaseName, strError);
		return 0;
	}


	// allocate memory for the field descriptors
	pFldDesc = (pFLDDesc)malloc(curProps.iFields * sizeof(FLDDesc));
	if (pFldDesc == NULL)
	{
		// Throw exception for DBIERR_NOMEMORY
		throw new CBdeException(DBIERR_NOMEMORY);
		return 0;
	}

	dbiResult = DbiGetFieldDescs(m_hCursor, pFldDesc);
	if (dbiResult != DBIERR_NONE)
	{
		free(pFldDesc);
		strError.Format("Failed to retrieve field information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return 0;
	}

	UINT16 nFieldType = pFldDesc[nFieldNumber-1].iFldType;

	free(pFldDesc); // clean up the field descriptor
	return (int)nFieldType;
}


// function to get the filed type
// returns 0 on error or not a blob
int CBdeDatabase::GetBlobType(int nFieldNumber)
{
	// Throw an exception if not in edit mode
	if (!CheckValidCursor("Failed to get field type.")) return FALSE;
	if (!CheckEditMode("Failed to get field type.")) return FALSE;

	DBIResult dbiResult;
  CURProps curProps; // Table Properties
	pFLDDesc pFldDesc; // field information
	CString strError;

	// get the cursor properties for the table
  dbiResult = DbiGetCursorProps(m_hCursor, &curProps);
	if (dbiResult != DBIERR_NONE)
  {
		strError.Format("Failed to get cursor properties.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return 0;
  }

	// make sure the field number is valid
	if (nFieldNumber < 1 || nFieldNumber > curProps.iFields)
	{
		strError.Format("Invalid field index %d.  Valid numbers are between 1 and %d.", 
			nFieldNumber, curProps.iFields);
		throw new CBdeException(DBIERR_NONE, BDEEXERR_INVALIDFIELDINDEX,
			m_szTableName, m_szDatabaseName, strError);
		return 0;
	}


	// allocate memory for the field descriptors
	pFldDesc = (pFLDDesc)malloc(curProps.iFields * sizeof(FLDDesc));
	if (pFldDesc == NULL)
	{
		// Throw exception for DBIERR_NOMEMORY
		throw new CBdeException(DBIERR_NOMEMORY);
		return 0;
	}

	dbiResult = DbiGetFieldDescs(m_hCursor, pFldDesc);
	if (dbiResult != DBIERR_NONE)
	{
		free(pFldDesc);
		strError.Format("Failed to retrieve field information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return 0;
	}

	UINT16 nFieldType = pFldDesc[nFieldNumber-1].iFldType;
	UINT16 nFieldSubType = pFldDesc[nFieldNumber-1].iSubType;

	free(pFldDesc); // clean up the field descriptor

	if (nFieldType != fldBLOB) return 0;
	return (int)nFieldSubType;
}



// function to get the field name from it's number
CString CBdeDatabase::GetFieldName(int nFieldNumber)
{
	if (!CheckValidCursor("Failed to get field name.")) return "";

	DBIResult dbiResult;
	CURProps CurProps;
	pFLDDesc pFldDesc;
	CString strError;
	CString strRetVal;

	dbiResult = DbiGetCursorProps(m_hCursor, &CurProps);

	if (dbiResult != DBIERR_NONE)
	{
		strError.Format("Failed to cursor properties in table %s.",
			m_szTableName);
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		return "";
	}

	// make sure the number is within the proper range
	if (nFieldNumber < 1 || nFieldNumber > CurProps.iFields)
	{
		strError.Format("Invalid field index %d.  Valid numbers are between 1 and %d.", 
			nFieldNumber, CurProps.iFields);
		throw new CBdeException(DBIERR_NONE, BDEEXERR_INVALIDFIELDINDEX,
			m_szTableName, m_szDatabaseName, strError);
		return "";
	}


	// allocate memory for the field descriptor
	pFldDesc = (pFLDDesc)malloc(CurProps.iFields * sizeof(FLDDesc));
	if (pFldDesc == NULL)
	{
		// Throw exception for DBIERR_NOMEMORY
		throw new CBdeException(DBIERR_NOMEMORY);
		return "";
	}

	dbiResult = DbiGetFieldDescs(m_hCursor, pFldDesc);

	if (dbiResult != DBIERR_NONE)
	{
		// Throw exception here
		strError.Format("Failed to get field information.");
		throw new CBdeException(dbiResult, m_szTableName, m_szDatabaseName, strError);
		free(pFldDesc);
		return "";
	}

	strRetVal.Format("%s", pFldDesc[nFieldNumber-1].szName);
	free(pFldDesc);
	return strRetVal;
}


// returns the 1 based index of a field name
// returns 0 on error
int CBdeDatabase::FieldNumberFromName(LPCTSTR szFieldName)