If you like SQL you could just use it. You could use H2 or SQLite as local databases which live in memory or on a single file on your hard drive.
You could just load data there and do all the manipulation in SQL.
You can just write the code ‘free’ or use the prepared nodes for databases that would translate into SQL - but if you are familiar with it you might not need it.
Red DB connections would just transport the command to the database and you would have to do everything yourself (create tables etc) or the brown connections where you select one table and do the manipulations there.
This example is for a big data DB but the system and nodes are the same: