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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, 7 insertions, 5 deletions
diff --git a/railties/guides/source/association_basics.textile b/railties/guides/source/association_basics.textile index f6d61373e1..f22f41e8b1 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+ @@ -550,6 +550,8 @@ build_customer create_customer </ruby> +NOTE: When initializing a new +has_one+ or +belongs_to+ association you must use the +build_+ prefix to build the association, rather than the +association.build+ method that would be used for +has_many+ or +has_and_belongs_to_many+ associations. To create one, use the +create_+ prefix. + h6(#belongs_to-association). <tt><em>association</em>(force_reload = false)</tt> The <tt><em>association</em></tt> method returns the associated object, if any. If no associated object is found, it returns +nil+. @@ -817,6 +819,8 @@ build_account create_account </ruby> +NOTE: When initializing a new +has_one+ or +belongs_to+ association you must use the +build_+ prefix to build the association, rather than the +association.build+ method that would be used for +has_many+ or +has_and_belongs_to_many+ associations. To create one, use the +create_+ prefix. + h6(#has_one-association). <tt><em>association</em>(force_reload = false)</tt> The <tt><em>association</em></tt> method returns the associated object, if any. If no associated object is found, it returns +nil+. @@ -1131,7 +1135,7 @@ 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. @@ -1560,7 +1564,7 @@ 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> @@ -1876,8 +1880,6 @@ Extensions can refer to the internals of the association proxy using these three h3. Changelog -"Lighthouse ticket":http://rails.lighthouseapp.com/projects/16213-rails-guides/tickets/11 - * April 7, 2010: Fixed document to validate XHTML 1.0 Strict. "Jaime Iniesta":http://jaimeiniesta.com * April 19, 2009: Added +:touch+ option to +belongs_to+ associations by "Mike Gunderloy":credits.html#mgunderloy * February 1, 2009: Added +:autosave+ option "Mike Gunderloy":credits.html#mgunderloy |