Using a Parameterized Query
I try a simple example that retrieves records with an age field from a table in a Microsoft Access database:
#include <atldbcli.h>
CDataSource connection;
CSession session;
CCommand<CAccessor<CArtists> > artists;
connection.Open(CLSID_MSDASQL, "NWind", "sa", "");
session.Open(connection);
// Set the parameter for the query
artists.m_nAge = 30;
artists.Open(session, "select * from artists where age > ?");
// Get data from the rowset
while (artists.MoveNext() == S_OK)
{
cout << artists.m_szFirstName;
cout << artists.m_szLastName;
}
The user record, CArtists, looks like this:
class CArtists
{
public:
// Data Elements
CHAR m_szFirstName[20];
CHAR m_szLastName[30];
short m_nAge;
// output binding map
BEGIN_COLUMN_MAP(CArtists)
COLUMN_ENTRY(1, m_szFirstName)
COLUMN_ENTRY(2, m_szLastName)
COLUMN_ENTRY(3, m_nAge)
END_COLUMN_MAP()
// parameter binding map
BEGIN_PARAM_MAP(CArtists)
COLUMN_ENTRY(1, m_nAge)
END_PARAM_MAP
};
the example works but if I try the same with CHAR m_szFirstName:
BEGIN_PARAM_MAP(CArtists)
COLUMN_ENTRY(1, m_szFirstName)
END_PARAM_MAP
};
strcpy(artists.m_szFirstName, "a");
artists.Open(session, "select * from artists where name like '%?%' ");
I have no result...
What can I do??
thanks,
Mreclo Modolo

