Many apps fancy an export function. So wouldn4t it be nice to be able to easily save that result you4ve got there as an Excel sheet?
ODBC does make this possible, but there4s one little drawback: Using ODBC the usual way there has to be a registered datasource (DSN) in the ODBC manager.
This is not very useful because you4d have to install that DSN locally on every machine that should support your export function.
Omiting the DSN tag in the connect string of CDatabase:OpenEx() gives us the opportunity to refer the ODBC-Driver directly using its name so we don4t have to have a DSN registered.
This, of course, implies that the name of the ODBC-Driver is exactly known.
If you just want to test if a certain driver is present (to show the supported extensions in the CFileOpenDlg for example) just try to CDatabase:OpenEx() it.
If it isn4t installed an exception gets thrown.
To create and write to that Excel sheet you simply use SQL as shown in the code sample below.
In order to get the code below going you have to
- have <afxdb.h> included
- have an installed ODBC-driver called “MICROSOFT EXCEL DRIVER (*.XLS)”
// this example creates the Excel file C:DEMO.XLS, puts in a worksheet with two
// columns (one text the other numeric) an appends three no-sense records.
CString sDriver = “MICROSOFT EXCEL DRIVER (*.XLS)”; // exactly the same name as in the ODBC-Manager
CString sExcelFile = “c:\demo.xls”; // Filename and path for the file to be created
// Build the creation string for access without DSN
// Create the database (i.e. Excel sheet)
if( database.OpenEx(sSql,CDatabase::noOdbcDialog) )
// Create table structure
sSql = “CREATE TABLE demo (Name TEXT,Age NUMBER)”;
// Insert data
sSql = “INSERT INTO demo (Name,Age) VALUES (‘Bruno Brutalinsky’,45)”;
sSql = “INSERT INTO demo (Name,Age) VALUES (‘Fritz Pappenheimer’,30)”;
sSql = “INSERT INTO demo (Name,Age) VALUES (‘Hella Wahnsinn’,28)”;
// Close database
TRACE1(“Driver not installed: %s”,sDriver);