5 Things Learned:

1. How to design ER diagrams and normalize tables.
2. Writing SQL queries for CRUD operations.
3. Using keys (primary, foreign) to enforce relationships.
4. How indexes improve lookup performance.
5. Basics of transactions and data integrity.

3 Questions I Still Have:

1. How are distributed databases managed efficiently?
2. How is SQL so extensible but also readable?
3. How does query optimization work behind the scenes?