This question has been answered, but I was in the mood and toyed around with R and my new favourite way to get data in and out of R (and KNIME): SQLite
You can do all the stuff you want in R and then put the results into SQLite by either creating new data sets or appending the stuff to existing ones. Gives you a lot of flexibility.
kn_example_r_sqlite_multiple_tables.knwf (39.9 KB)