If you struggle and even are afraid to code in SQL, you definitely have to check this presentation out. How to write SQL for humans?!

1. 8th of October 2014
Zen SQL
Best practices to query and database design
by Clément Prévost

2. 8th of October 2014
The Zen way to SQL
● State of the art
● Readability best practices:
a. Database schema
b. Query

3. 8th of October 2014
State of the art
● ORM (Doctrine, ActiveRecord, ...)
○ Hides the database schema and queries, follow your
applicative coding best practices
● Query Builder (ZendDbSql, …)
○ Hides the queries, not the schema
● Raw (Migration scripts, performance critical task,
Analytics)
○ DIY

4. 8th of October 2014
The Zen way to SQL
● State of the art
● Readability best practices:
a. Database schema
b. Query

5. a) Database schema best practices
8th of October 2014
A. KISS
○ Beware of overengineering
○ Don’t let optimizations get in the way of simplicity
B. Explicitness is the key
○ Ban abbreviations, “status” column and add
comments
C. Your business WILL evolve, same with your schema
○ Never be afraid to refactor, rename and move stuff
around

6. 8th of October 2014
Case study: Database schema BP

7. 8th of October 2014
1
3
2
1
2
3
3

8. 8th of October 2014
The Zen way to SQL
● State of the art
● Readability best practices:
a. Database schema
b. Query

9. 8th of October 2014
b) Query best practices
A. Comments and documentation, Avoid deep nesting,
Reuse external libraries
B. Know your enemy: Long vs. complex queries
C. Tools: IDE, Database specificity, SQL capabilities

10. 8th of October 2014

11. 8th of October 2014

12. 8th of October 2014

13. 8th of October 2014
Key things to remember
● Work it step by step
○ Have a perfect schema, then work on beautiful
queries
● Know your tools, learn advanced SQL
● You already know how
○ Good coding practices also apply to SQL (queries
AND schema)

14. 8th of October 2014
Questions ?
For online questions, please leave a comment on the article.

15. 8th of October 2014
Join the community !
(in Paris)
Social networks :
● Follow us on Twitter : https://twitter.com/steamlearn
● Like us on Facebook : https://www.facebook.com/steamlearn
SteamLearn is an Inovia initiative : inovia.fr
You wish to be in the audience ? Contact us at
learn@steamhouse.fr

16. 8th of October 2014
Sources
1. http://www.slideshare.net/Samuel90/software-development-vs-software-maintenance
2. http://code.tutsplus.com/tutorials/top-15-best-practices-for-writing-super-readable-code--net-
8118
3. http://www.postgresql.org/docs/9.3/static/view-pg-available-extensions.html
4. http://postgres-bits.herokuapp.com/
5. http://www.postgresql.org/docs/9.3/static/index.html