When something unexpected happens, you should know about it immediately to make debugging and fixing the problem easier. Discusses ActiveRecord persistence APIs.

1. Blow up when
things are wrong
ActiveRecord edition
Vesa Vänskä, Kisko Labs
Helsinki Ruby Brigade, Rails Girls

2. When something
is wrong, you
should know
about it as fast as
possible

3. #save vs #save!

4. foo.save!
# or
if foo.save
# success
else
# fail
end

5. The case of
updating
attributes

6. Validations Callbacks
#update_attributes ✔ ✔
#update_attribute ✖ ✔

7. Question

8. Which of #decrement,
#decrement!, and
#decrement_counter
skip validations/
callbacks?

9. Validations Callbacks
#decrement ✔ ✖
#decrement! ✖ ✔
#decrement_counter ✖ ✖

10. http://guides.rubyonrails.org/
active_record_validations_callba
cks.html

11. ATK
Do Not Want
RubyGem
https://github.com/
garybernhardt/do_not_want

12. Making it simpler

13. In Rails 3.2.7 the
#update_attribute method was
actually deprecated

14. 14.6.2012 – #update_attribute is deprecated in 3.2
branch
14.6.2012 – #update_attribute was removed from 4.0
branch
24.7.2012 – #update_column was deprecated in 4.0
branch
26.7.2012 – Rails 3.2.7 release
30.7.2012 – #update_column is undeprecated in 4.0
branch
1.8.2012 – #update_attribute is undeprecated in 3.2
branch
25.8.2012 – #update_attribute is put back in 4.0
branch
9.8.2012 – Rails 3.2.8 release

15. • https://github.com/rails/rails/commit/
b081f6b59fb3f15d12043072ad9b331ffd2bc56e
• https://github.com/rails/rails/pull/6738
• https://github.com/rails/rails/pull/1190
• https://github.com/rails/rails/commit/
4ac81de52fbcdabc68f6d1fa8a5ee9ff7fff7df1
• https://github.com/rails/rails/commit/
50bdb924ba26999a468ec4844917cefec39ba08c
• https://github.com/rails/rails/commit/
81542f95d25825a7d3eff87d6f706661bf553b18
Links

16. I

17. What is the
current status?

18. After all this
•In Rails 4 the recommended way
is to use #update with a hash
•#update_attributes is aliased to
#update
•#update_attribute is still skipping
validations

19. Vesa's laws of
updating attributes
1. Use #update_attributes or use
setters and #save/#save!
2. All other methods of updating
attributes need an accompanying
comment that explains why you
didn't follow the first rule.

20. Useless ActiveResource
information
•ActiveResource #update_attribute
will run validations normally

21. Extra Ruby tip

22. {foo: "bar"}[:foo]
{foo: "bar"}.fetch(:foo)

23. {foo: "bar"}[:foo] #=> "bar"
{foo: "bar"}.fetch(:foo)
#=> "bar"

24. {foo: "bar"}[:whatevs]
{foo: "bar"}.fetch(:whatevs)

25. {foo: "bar"}[:whatevs] #=> nil
{foo: "bar"}.fetch(:whatevs)
#=> KeyError: key not
found: :whatevs

26. {foo: "bar"}
.fetch(:whatevs, :not_found)
#=> :not_found
{foo: "bar"}
.fetch(:whatevs) { 1 + 1 }
#=> 2

27. Thank you!
twitter.com/vesan
vesavanska.com