ldl++(5)> query delta(I,X,Y,C)
query delta(I,X,Y,C)

Querying : delta(I,X,Y,C) ... 
	(0, a, a, 0)
	(0, b, b, 0)
	(0, c, c, 0)
	(0, d, d, 0)
	(1, a, b, 2)
	(1, a, c, 4)
	(1, a, d, 5)
	(1, b, c, 3)
	(1, b, d, 1)
	(1, c, d, 2)
	(2, a, d, 3)

	The number of records is 11.
ldl++(6)>