What is an interactive report? What is the obvious difference of such report compared with classical type reports?

A classical report connects of one program that creates a single list. This means that when the list is displayed, it has to contain all data requested, regardless of the number of details the user wants to see.
Interactive reporting allows the user to participate in retrieving and presenting data at each level during the session. Instead of presenting one extensive and detailed list with classified information. With interactive reporting you can create a condensed basic list from which the user can call detailed information by positioning the cursor and entering commands.
Detailed information is presented in secondary list. A secondary list may either overlay the basic list completely or appear in an additional dialog window on the same screen. The secondary list can itself be interactive again. The basic list is not deleted when secondary list is created.

User can interact with system by
- double clicking or pressing f2
- selecting menu option

Like classical report the interactive report is also event driven. Both the action mentioned above trigger events and code is written to handle these events. The events triggered by this action are as follows

- At line-selection
- At user-command

Interactive report consists of one basic list and 20 secondary list. Basic list is produced by START-OF_SLECTION event. When the user double clicks on the basic list or chooses the menu option, the secondary list is produced. All the vents associated with classical report except end-of-page are applicable only to basic list.