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Diffstat (limited to 'guides/source/nested_model_forms.md')
| -rw-r--r-- | guides/source/nested_model_forms.md | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/guides/source/nested_model_forms.md b/guides/source/nested_model_forms.md index 855fab18e3..1937369776 100644 --- a/guides/source/nested_model_forms.md +++ b/guides/source/nested_model_forms.md @@ -1,4 +1,6 @@ -Rails nested model forms +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + +Rails Nested Model Forms ======================== Creating a form for a model _and_ its associations can become quite tedious. Therefore Rails provides helpers to assist in dealing with the complexities of generating these forms _and_ the required CRUD operations to create, update, and destroy associations. @@ -17,9 +19,9 @@ Model setup To be able to use the nested model functionality in your forms, the model will need to support some basic operations. -First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The `fields_for` form helper will look for this method to decide whether or not a nested model form should be build. +First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The `fields_for` form helper will look for this method to decide whether or not a nested model form should be built. -If the associated object is an array a form builder will be yielded for each object, else only a single form builder will be yielded. +If the associated object is an array, a form builder will be yielded for each object, else only a single form builder will be yielded. Consider a Person model with an associated Address. When asked to yield a nested FormBuilder for the `:address` attribute, the `fields_for` form helper will look for a method on the Person instance named `address_attributes=`. @@ -54,6 +56,9 @@ class Person < ActiveRecord::Base end ``` +NOTE: For greater detail on associations see [Active Record Associations](association_basics.html). +For a complete reference on associations please visit the API documentation for [ActiveRecord::Associations::ClassMethods](http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html). + ### Custom model As you might have inflected from this explanation, you _don't_ necessarily need an ActiveRecord::Base model to use this functionality. The following examples are sufficient to enable the nested model form behavior: @@ -220,6 +225,6 @@ As you can see it has generated 2 `project name` inputs, one for each new `proje You can basically see the `projects_attributes` hash as an array of attribute hashes, one for each model instance. -NOTE: The reason that `fields_for` constructed a form which would result in a hash instead of an array is that it won't work for any forms nested deeper than one level deep. +NOTE: The reason that `fields_for` constructed a hash instead of an array is that it won't work for any form nested deeper than one level deep. TIP: You _can_ however pass an array to the writer method generated by `accepts_nested_attributes_for` if you're using plain Ruby or some other API access. See (TODO) for more info and example. |