text: CREATE INDEX IDX_SUPPLIER_NATION_KEY ON SUPPLIER (S_NATIONKEY);
  CREATE INDEX IDX_PARTSUPP_PARTKEY ON PARTSUPP (PS_PARTKEY);
  CREATE INDEX IDX_PARTSUPP_SUPPKEY ON PARTSUPP (PS_SUPPKEY);
  CREATE INDEX IDX_CUSTOMER_NATIONKEY ON CUSTOMER (C_NATIONKEY);
  CREATE INDEX IDX_NATION_REGIONKEY ON NATION (N_REGIONKEY);
  