objects explanation

Can u explain me about below objects i.e what tables , t.codes used , etc.....

• Developed a report to display vendor details on basic list and Purchasing Header details for the selected vendor in the next secondary list and display the purchasing items for the selected purchase document in next list and display the material details for the selected material in next list.

• Developed a complex report to display Customer wise sales order report, selection screen criteria were customer number range and order number range.

• Developed a BDC program for uploading the data of sales orders using transaction VA01.

• Developed a BDC program for uploading the material master data from the legacy system to SAP system through the transaction code MM02.