Invalid extracture structure

Hi ALL,

i need your help.

WE create a generic data source based on Table MARC, but got an error----Invalid extracture structure because of Unit and currency in two reference tabels MARA and T001. We create a database view. In this view we choose all fieds of MARC and add MARA and T001 into this view. In this view we also add unit and currency. No error for this data source based on view. But we test this datasouce and found data records incorrect. we are sure that in the view 3 tables were joined although we did not do any join.

How to solve this problem!

thanks in advance!

BR,

Gang