cascading prompt means t is nested.means we can aaply the
prompt like this.region to country,country to state,state to
city.
step1;select objects and double click.then draw the region
to query panel then select operator and operand as select
new prompt.after type and drag the country to query panel
then select operator then operand as select new prompt. like
that we can create.then finally run query.then asks to enter
values 
for region after enter the values for country.
        by emambasha.shaik