i have create one Z table in that i have 3 fileds .
whenever user insert the data 2 fileds data should be unique.
the table i have created as below .
Z_CABJN Z_VBELN Z_POSNR
x 1000 10
y 1000 20
z 1000 30
my table shou not accept
x 1000 40
for ever change of Z_VBELN / Z_POSNR i sholud have new