Is there a way to check if the data is already created in SAP R/3 before uploading through BODS.For example before creating a material in SAP i want to check if the material is already present.This precheck should be incorporated in BODS.
If it is external number and if you are assigning the material number then you can check that in MARA table MATNR field in sap.
If you are sending blank in MATNR field in your idoc load, you should load your legacy reference into MARA.BISMT field so that you before loading you can import the MARA data from sap into database and compare against it.