this is what you need in a header file (see SQLApp.h):
#define SCHEMADIALECT <plugin/sqlite3/Sqlite3Schema.h> //not sure atm which file defines the SCHEMADIALECT for MySQL!!!
#define MODEL <SQLApp/SQLApp.sch> //your .sch file here
#include <Sql/sch_header.h>
and in a sourcefile
#define SCHEMADIALECT <plugin/sqlite3/Sqlite3Schema.h> //again you need the one for MySQL
#include <Sql/sch_source.h>