Data Integrity

Be confident in your data. Less bugs. Moar happy.

Delivered at hsv.rb - http://www.meetup.com/hsv-rb/events/192571982/

Transcript

1. EBUBJOUFHSJUZ ITWSC
2. +BZ
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3. JBNWFSZDPN
6. JNNFSTJWF
   CPPUDBNQT DPOTVMUJOH XSJUJOH
9. EBUBJOUFHSJUZ
10. EBUBJOUFHSJUZ
11. EBUBJOUFHSJUZ
12. EBUBJOUFHSJUZ
13. USVTU
    ZPVS
    EBUB
14. UIF
    EBUBT create_table :products do |t| t.string :description t.boolean :active t.decimal :price end
15. XIBU
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    TUBUF product = Product.all.sample product.description => ?
16. XIBU
    UIF
    TUBUF product = Product.all.sample product.description => “doge cannon”
17. XIBU
    UIF
    TUBUF product = Product.all.sample product.description => ‘’
18. XIBU
    UIF
    TUBUF product = Product.all.sample product.description => nil WOMP
19. XIBU
    UIF
    TUBUF product = Product.all.sample product.active => ?
20. XIBU
    UIF
    TUBUF product = Product.all.sample product.active => true
21. XIBU
    UIF
    TUBUF product = Product.all.sample product.active => false
22. XIBU
    UIF
    TUBUF product = Product.all.sample product.active => nil WAT
23. product = Product.new product.description.upcase NoMethodError: undefined method `upcase` for nil:NilClass
24. product = Product.new product.description.to_s.upcase
25. product.price * TAX_RATE NoMethodError: undefined method `*` for nil:NilClass
26. (product.price || 0) * TAX_RATE
27. XIBU
    JT
    OPUIJOH
28. DPOTUSBJOUT
29. t.string :description, null: false t.boolean :active, null: false t.decimal :price, null: false
30. USVTU
31. product = Product.new product.description.upcase => “KITTEH GOOGLEH EYES” &WFSZ 4JOHMF 5JNF
32. TFOTJCMF EFGBVMUT
33. TUSJOHT t.string :description, null: false, default: ‘’
34. CPPMFBOT t.boolean :active, null: false, default: false
35. EFDJNBMT t.decimal :price, null: false
36. NPBS
    DPOTUSBJOUT 
37. TUSJOHT t.string :description, null: false, default: ‘’, limit: 100
38. EFDJNBMT t.boolean :active, null: false, scale: 2, precision: 5
39. VOJRVFOFTT
40. UIF
    EBUBT create_table :users do |t| t.string :email, null: false end
41. User.create(email: “jay@bignerdranch.com”) User.create(email: “jay@bignerdranch.com”) User.all => [#<User id: 1, email: “jay…”>, #<User id: 2, email: “jay…”>] who even are you???
42. validate :email, uniqueness: true
43. WBMJEBUJPOT  EPOU
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44. robots.thoughtbot.com/the-perils-of-uniqueness-validations
45. JOEJDFT create_table :users do |t| t.string :email, null: false t.index :email, unique: true end
46. SFGFSFODJBM JOUFHSJUZ
47. UIF
    EBUBT create_table :purchases do |t| t.integer :product_id, null: false t.integer :user_id, null: false t.index %i(product_id, user_id), unique: true end
48. user = User.find(1) product = Product.find(1) Purchase.create(user: user, product: product) product.destroy Purchase.last => #<Purchase id: 1, product_id: 1, user_id: 1> _.product => nil but it dead???
49. dependent: :destroy dependent: :delete dependent: :delete_all
50. HSFBU  VOUJM
    JU
    JTOU
51. user = User.find(1) product = Product.find(1) Purchase.create(user: user, product: product) product.delete Purchase.last => #<Purchase id: 1, product_id: 1, user_id: 1> WOMP
52. HFN
    JOTUBMM
    GPSFJHOFS create_table :purchases do |t| # … t.foreign_key :products, dependent: :delete t.foreign_key :users, dependent: :restrict end
54. SBJMTSBJMT
55. CF
    DPOGJEFOU
56. BWPJE
    CVHT
57. IBWF
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58. bignerdranch.com/blog/coding-rails-with-data-integrity ! bignerdranch.com/blog/coding-rails-with-data-integrity-part-2 ! bignerdranch.com/blog/coding-rails-with-data-integrity-part-3 CMPHT
59. 5IBOLT !JBNWFSZ