this page has references to videos if you like to learn about databases. This is just a reference and the credit goes to the people who have created the videos and i am just referring to those for your reference to save a chunk of your googling time.
A link to business rules https://www.youtube.com/watch?v=0v4cxM_1lMI
A link to Database keys https://www.youtube.com/watch?v=8wUUMOKAK-c
Learn with lucid chart
kahoot quiz on database fundamentals for your reference
Revision on Database Fundamentals1
Revision on Database Fundamentals2
Learn to create tables with primary keys, foreign keys along with unnamed and named constraints at
column level and table level
Basics of SQL