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Diffstat (limited to 'railties/guides/source/association_basics.textile')
| -rw-r--r-- | railties/guides/source/association_basics.textile | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/railties/guides/source/association_basics.textile b/railties/guides/source/association_basics.textile index 62abc40c81..e5b8c73c43 100644 --- a/railties/guides/source/association_basics.textile +++ b/railties/guides/source/association_basics.textile @@ -65,7 +65,7 @@ To learn more about the different types of associations, read the next section o h3. The Types of Associations -In Rails, an _association_ is a connection between two Active Record models. Associations are implemented using macro-style calls, so that you can declaratively add features to your models. For example, by declaring that one model +belongs_to+ another, you instruct Rails to maintain Primary Key–Foreign Key information between instances of the two models, and you also get a number of utility methods added to your model. Rails supports six types of association: +In Rails, an _association_ is a connection between two Active Record models. Associations are implemented using macro-style calls, so that you can declaratively add features to your models. For example, by declaring that one model +belongs_to+ another, you instruct Rails to maintain Primary Key–Foreign Key information between instances of the two models, and you also get a number of utility methods added to your model. Rails supports six types of associations: * +belongs_to+ * +has_one+ @@ -165,6 +165,12 @@ class Paragraph < ActiveRecord::Base end </ruby> +With +:through => :sections+ specified, Rails will now understand: + +<ruby> +@document.paragraphs +</ruby> + h4. The +has_one :through+ Association A +has_one :through+ association sets up a one-to-one connection with another model. This association indicates that the declaring model can be matched with one instance of another model by proceeding _through_ a third model. For example, if each supplier has one account, and each account is associated with one account history, then the customer model could look like this: @@ -1135,7 +1141,7 @@ h6(#has_many-collection-find). <tt><em>collection</em>.find(...)</tt> The <tt><em>collection</em>.find</tt> method finds objects within the collection. It uses the same syntax and options as +ActiveRecord::Base.find+. <ruby> -@open_orders = @customer.orders.find(:all, :conditions => "open = 1") +@open_orders = @customer.orders.all(:conditions => "open = 1") </ruby> NOTE: Starting Rails 3, supplying options to +ActiveRecord::Base.find+ method is discouraged. Use <tt><em>collection</em>.where</tt> instead when you need to pass conditions. @@ -1564,7 +1570,7 @@ h6(#has_and_belongs_to_many-collection-find). <tt><em>collection</em>.find(...)< The <tt><em>collection</em>.find</tt> method finds objects within the collection. It uses the same syntax and options as +ActiveRecord::Base.find+. It also adds the additional condition that the object must be in the collection. <ruby> -@new_assemblies = @part.assemblies.find(:all, +@new_assemblies = @part.assemblies.all( :conditions => ["created_at > ?", 2.days.ago]) </ruby> |