The document discusses whether clean code principles can be applied to PL/SQL. It defines clean code as code that is written by someone who cares and for people first rather than computers. While clean code principles primarily target modern object-oriented languages, the document argues that many of the principles directly apply to PL/SQL as well, since it is compiled, imperative/procedural, and structured similarly to Java. Specific clean code topics like meaningful naming, formatting, comments, functions, and unit testing are examined in the context of PL/SQL. The conclusion is that clean code principles apply to PL/SQL to a certain extent and the document encourages readers to consider applying them.

1. Can PL/SQL
Be Clean?
AOUG, Oct. 2013
Peter Kofler, ‘Code Cop’
@codecopkofler
www.code-cop.org
Copyright Peter Kofler, licensed under CC-BY.

2. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Peter Kofler
• Ph.D. (Appl. Math.)
• Software Developer
for 14 years
• “fanatic about code quality”
• Pair Programming #CodeCopTour

3. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Agenda
Define Clean Code
● Define PL/SQL
● Apply Clean Code to PL/SQL
● Examples
● Discussion
●

4. What is Clean Code?

5. “Craftsmanship
Over Crap“
(Robert C. Martin)

6. “Clean code looks
like it was written
by someone who
cares.”
(Michael Feathers)

7. Rule 1)
Written by
someone who
cares.

8. What is Clean Code?

9. Clean Code

10. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Clean Code is Not New
Clean Coder, 2011
● Clean Code, 2008
● Implementation Patten, 2007
● Agile Software Development, 2002
● The Pragmatic Programmer, 1999
● Refactoring, 1999
● Code Complete 1st Ed, 1993 (!)
●

11. Quick And Dirty

12. Code Complete

13. “Write Programs for
People First,
Computers Second.”
(Steve McConnell)

14. Rule 2)
Written for
People First.

15. So how would
You
like the code to be?
(besides working correctly)

16. Code which does
not make me want
to kill the author.
http://programmers.stackexchange.com/a/13594/15057

17. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Easy and Simple!
Easy to read.
● Easy to follow.
● Easy to understand.
● Easy to modify.
● Easy to test.
● Easy ...
●
http://stackoverflow.com/a/954582/104143

18. Procedural Language/
Structured Query Language

19. Should you write
PL/SQL with care?

20. Should you write
PL/SQL for people?

21. Tadaaa!

22. Clean PL/SQL
looks like it was
written by someone who cares.

23. Write PL/SQL for
People First,
Databases Second.

24. But...

25. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
PL/SQL is not Java
• Clean Code targets “modern” languages
– Java, C#
– Ruby, Python
– maybe C++
• Clean Code is about
– Object Orientation
– Test Driven Development

26. Do these guidelines
apply to PL/SQL?

27. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
PL/SQL is...
• compiled
• imperative/procedural with modules
– function/procedure/package
• structured
– if/loop/continue/exit
– with exceptions
• static typed with strong type safety
• kind of object-orientated (version 8)
http://en.wikipedia.org/wiki/PL/SQL

28. Sounds much like
Java to me ;-)

29. Examples from

30. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Meaningful Names

Names should reveal intent.

Use pronounceable names.

Use Problem Domain Names.
e.g. http://www.zero1design.com/2011/10/31/cleaner-code-in-t-sql-part-1-%E2%80%93-naming-stored-procs-views/

31. http://theprofoundprogrammer.com/post/26561881517/text-single-letter-variables-who-the-fuck-do

32. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Other Chapters
●
Formatting 
●
Comments 
●
Functions 
●
Unit Testing 

33. /3 of “Clean Code”
applies directly
1

35. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Single Responsibility Principle
„SRP“
● Do one thing.
● One reason for a function to change.
● One level of abstraction per function.
● Maybe applies to packages as well.
●

36. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Other Object Oriented Stuff?
●
Encapsulation 
●
Coupling (between packages) 
●
Cohesion 
●
Cyclomatic Complexity 

37. ½ of “Clean Code”
applies (in some way)

38. Conclusion

39. 1)
Clean code always
looks like it was
written by someone who cares.

40. 2)
Clean Code Applies
to PL/SQL
(at least to a certain extend)

41. 3) Read It!

42. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
Peter Kofler
@codecopkofler
www.code-cop.org

43. PETER KOFLER, CODE-COP.ORG
FANATIC ABOUT CODE QUALITY
CC Images
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cleaning: http://www.flickr.com/photos/inf3ktion/4477642894/
●
dump: http://www.flickr.com/photos/sanmartin/2682745838/
●
thumb: http://www.flickr.com/photos/leehaywood/4481372869/
●
knife: http://www.flickr.com/photos/21232564@N06/2234726613/
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finish: http://www.flickr.com/photos/jayneandd/4450623309/