how to use index with this class

I need some example to use a dbf file with index.

vfp example

Table Structure rec_cc.dbf
rec=char(2)
tipo_imp=char(1)
nro_imp=numeric(10,0)
fecha=date(8)

Data on table rec_cc.dbf
rec='1'
tipo_imp='I'
nro_imp=1

rec='2'
tipo_imp='I'
nro_imp=2

rec='3'
tipo_imp='I'
nro_imp=3


Index Primario
recurso+tipo_imp+STR(nro_imp,10,0)

for open table
->use c:\rec_cc.dbf

for use index
->set order to primario

->brow 'Show all data

->set key to '1'+'I'+STR(1,10,0) 'Show only one record

Can I do it with your class? or Can I run SQL query?