Relation_Examples.md

Relations

The character * means UNIQUE

One To Many (Many to One)

Authors

id*	full_name*
1	Brian Tracy
2	Robert T. Kiyosaki
3	Rolf Dobelli
4	Jane Austen

Books

id*	book_name	author_id (authors.id)
1	The Art of the Good Life	3
2	Rich Dad, Poor Dad	2
3	Time Management	1
4	Pride and Prejudice	4
5	The Business of the 21st Century	2
6	Sense and Sensibility	4
7	Emma	4
8	The Psychology of Achievement	1

One To One

Teachers

id*	full_name*
1	John Doe
2	Dudley Taylan
3	Jamal Detrick
4	Fannie Warntz

Classes

id*	name	teacher_id*
1	ABC	3
2	DEF	4
3	QWERTY	2
4	ASDFGH	1

Many to Many

Categories

id*	category_name*
1	Programming
2	Media
3	Graphics
4	News

Posts

id*	title
1	How to use Flask?
2	Python's author is resigning!!
3	Uploading Media on Flask
4	Version Control System for Designers

Posts_Categories (Association Table)

post_id + category_id should be unique next to each other!!*

post_id	category_id
1	1
2	1
2	4
3	1
3	2
4	3