Database: What's the difference between set, bag, and list?

In database course of Carnegie Melon University, Professor Andy mention several import concepts of database, set, list and bag.

What’s the difference? Here is the answer.

Reference

1. https://cs.wellesley.edu//~cs230/spring07/lectures/lec13_sets_bags_tables/lec13_sets_bags_tables.pdf

2. Stackoverflow: Difference between Set and Bag in Hibernate

3. CMU Database Systems - 01 Course introduction & Relational Data Model (Fall 2018)