ALTER TABLE X
ADD CONSTRAINT C_X_NN
CHECK ( (
DECODE (weight, NULL, 0, 1) +
DECODE (weight_unit, NULL, 0, 1) +
DECODE (length , NULL, 0, 1) +
DECODE (width , NULL, 0, 1) +
DECODE (height , NULL, 0, 1) +
DECODE (dimensional_unit , NULL, 0, 1)
) = 0
);