Regarding Start routine and field routine
Please correct me if I am wrong .
1 below code will check the material details from it_material with the source mat_plant ,if it is not euqal then it will delete the all data in the source_package .
2 if we are doing declaration in the global part of the start routine then will it available across endroutine and field level routine .
READ TABLE it_material INTO wa_material
WITH KEY material = <source_fields>-mat_plant
IF sy-subrc <> 0.