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Replace line items with chapters [ci skip]

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Line items are a holdover from when orders were used in the examples
instead of books.
This commit is contained in:
Ian Fleeton 2018-09-21 12:38:30 +01:00
parent 87a36ca665
commit f0c161cc05
1 changed files with 13 additions and 13 deletions
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26
guides/source/association_basics.md
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@ -1075,13 +1075,13 @@ end
You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models:
```ruby
class LineItem < ApplicationRecord
class Chapter < ApplicationRecord
belongs_to :book
end
class Book < ApplicationRecord
belongs_to :author
has_many :line_items
has_many :chapters
end
class Author < ApplicationRecord
@ -1089,16 +1089,16 @@ class Author < ApplicationRecord
end
```
If you frequently retrieve authors directly from line items (`@line_item.book.author`), then you can make your code somewhat more efficient by including authors in the association from line items to books:
If you frequently retrieve authors directly from chapters (`@chapter.book.author`), then you can make your code somewhat more efficient by including authors in the association from chapters to books:
```ruby
class LineItem < ApplicationRecord
class Chapter < ApplicationRecord
belongs_to :book, -> { includes :author }
end
class Book < ApplicationRecord
belongs_to :author
has_many :line_items
has_many :chapters
end
class Author < ApplicationRecord
@ -1779,8 +1779,8 @@ The `group` method supplies an attribute name to group the result set by, using
```ruby
class Author < ApplicationRecord
has_many :line_items, -> { group 'books.id' },
through: :books
has_many :chapters, -> { group 'books.id' },
through: :books
end
```
@ -1795,27 +1795,27 @@ end
class Book < ApplicationRecord
belongs_to :author
has_many :line_items
has_many :chapters
end
class LineItem < ApplicationRecord
class Chapter < ApplicationRecord
belongs_to :book
end
```
If you frequently retrieve line items directly from authors (`@author.books.line_items`), then you can make your code somewhat more efficient by including line items in the association from authors to books:
If you frequently retrieve chapters directly from authors (`@author.books.chapters`), then you can make your code somewhat more efficient by including chapters in the association from authors to books:
```ruby
class Author < ApplicationRecord
has_many :books, -> { includes :line_items }
has_many :books, -> { includes :chapters }
end
class Book < ApplicationRecord
belongs_to :author
has_many :line_items
has_many :chapters
end
class LineItem < ApplicationRecord
class Chapter < ApplicationRecord
belongs_to :book
end
```