Hi there @stevens_albert,
Welcome to KNIME Community Forum!
Considering you are new to KNIME I would suggest you to check learning section on KNIME home page for start. There you will find E-learning courses, link to YouTube channel, documentation and more.
Also KNIME offers a lot of workflow examples which are really a good way to learn how thing work in KNIME and how nodes are configured and used. Example workflows are accessible from KNIME Explorer within KNIME. Also you can search all nodes and workflows on KNIME Hub which is very useful. Additionally there is KNIME Community Forum which you already discovered. Feel free to ask questions and contribute back to community 
Related to databases I recommend you to use new Database Integration nodes from start as they are planned to be production ready in summer release and current DB nodes will become legacy. New DB Integration offers more nodes (like one @izaychik63 suggested) and possibilities.
Happy KNIMEing!
Br,
Ivan