* Initialize Cumulative Data Set ;
data prdsale_master(index=(ProdType Product Country State));
  set sashelp.prdsal2;
  rename monyr=date;
run;
* Add to Cumulative Data Set ;
data prdsale_master;
  set prdsale_master sashelp.prdsal3;
run;
* Check status of indexes ;
ods Select Attributes Indexes;
proc contents data=prdsale_master;
  title1 "CLASS data set attributes after concatenating";
run;