在下面的示例中，打开表并设置次序，然后用 relation() 显示关系。
close databases
open database (home( ) + 'samples\data\testdata')
use customer in 0 order cust_id && 打开表 customer
use employee in 0 order emp_id && 打开表customer
use orders in 0 order order_id && 打开表customer
select orders
set relation to emp_id into employee
set relation to cust_id into customer additive
? relation(1) && 显示cust_id
? relation(2) && 显示emp_id
? relation(3) && 显示空串