DSXchange

I am trying to build a generic parallell job using RCP which deletes or updates records in a database table using a dataset as a source. The tables consist of the same columns as the incoming dataset so RCP seems like a great idea, however all sources have different keys and the dataset schema-file doesn't seem to save key information! Therefore a update or delete cannot be preformed on the target table. I've tried to specify keys however the job crashes if a column is not in the dataset! So I don't know if I can build a generic job, could someone help me?