>Thank you Craig for the tip. What if I want to use 2 tables (parent-child) and I need to establish relations ? SQL commands are available only for databases.

Do a SQL Select that joins the parent and child tables together, so that each record contains one parent record along with its associated parent data. You can order the records first by parent, then by child within each parent, something like:

InvHead: (InvNo, CustNo, InvDate)
InvDetl: (InvNo, Item, Qty, Price, Disc)

Select InvHead.InvNo, CustNo, InvDate, Item, Qty, Price, Disc ;
  FROM InvHead, InvDetl ;
  INTO TABLE Temp ;
 WHERE InvHead.InvNo = InvDetl.InvNo ;
 ORDER BY InvDate, CustNo, InvHead.InvNo

creates a flat file sorted by Invoice Date, then by Customer, then by Invoice, with all line item detail in a single file. Creating a report from thsi should be fairly easy.