This currently only includes one function.
Allough is not complete I hope it shows how to set some of the field parameters.
Also look at MS Knowledge base article Q152688
SetAllowZeroLength( LPCTSTR lpszField, BOOL bSet )
lpszField is the field name to be modified,
bSet = TRUE for allowing zero length, FALSE for no zero length
How to Use:
CGeneralTableDef def( &MyDatabase ); // MyDatabase is a previously opened CDaoDatabase object def.Open( _T("A Table") ); def.SetAllowZeroLength( _T("AStringField"), TRUE ); // set allow zero length