select any row from instances of ROW
	where ( selected.needs_probe == true );
select any probe from instances of SP
	where ( selected.available == true );
probe.available = false;
row.needs_probe=false;
create object instance assignment of PAA;
relate row to probe across R2 using assignment;
generate PAA_A3:probe_assigned() to PAA assigner;
generate ROW2:probe_assigned() to row;