Opens or creates the given blob file and associates it with the Paradox database. This function must be
called before accessing records whose blob data is stored in a .MB file. It must also be called after
opening or creating the paradox database. If the blob data is contained in the record itself or can be
stored in the record, this function may not be called.
This function must be called after opening or creating the database file, because it uses the same file
open mode. If you call it before PX_open_file(3) or PX_create_file(3) it will quit with an
error.