@MichaelB you might want to check which kind of connection does what. If you want to use the results from a (brown) database connection and write that back (again) to a database you can use the: DB Connection Table Writer.
It is important to plan ahead what you want to do in your database and where you want to use KNIME. Both have their strengths. Maybe take a look at this example and follow the logic to see what can be done: