Check the example code :
http://www.sap-img.com/abap/bdc-example-using-table-control-in-bdc.htm
Simple example
If you see Sales order (VA01 ,VA02 ) -> here you will have one header and many line items.
In the line item ,we have material number ,item number,qty,price details.
We will get the file ,file contains one header and many line items.you need to write the diffrent logic.
Thanks
Seshu
