This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=SHSs9X6qiLc&list=PLVsNizTWUw7HhYtI-4GGmlJ5yxNdwNI_X ================================================================================ ================================================================================ Foreign key: the key which makes relationship between 2 tables ================================================================================ SQL: the language which DBMS can understand ================================================================================