This example program shows how a large database table can be exported to and 
imported from a spreadsheet file using virtual mode. 

First, run the section 1 to create a dBase file with random data.
Then, in section 2, the dBase file can be converted to any spreadsheet format
supported. Finally, in section 3, another dBase file can be created from a
selected spreadsheet file.

Please note that this example is mainly educational to show a "real-world"
application of virtual mode, but, strictly speaking, virtual mode would not
be absolutely necessary due to the small number of columns.

