Rails in one form multiple models--fields_for

With Field_for, you can generate forms to process data for two or more model objects

Let's look at an official example where there are two models of person and permission in a form, each of whom contains a permission

<%= form_for (@person) do |person_form| %>     <%= person_form.text_field:first_name%>     <%= person_form.text_field:last _name%>        <% fields_for:p ermission, @person. Permission do |permission_fields|%>       <%= Permission_fields.check_box:admin%>     <% end%>   <% End%>  

When a person contains multiple permission, the view code is as follows

<%= form_for (@person) do |person_form| %>     <%= person_form.text_field:first_name%>     <%= person_form.text_field:last _name%> for in         @person. Permissions%>     "permission[]" , permission do |permission_fields| %>         <%= permission_fields.check_box:admin%>       <% end%>     <% end%> <% End%>  

1, where "permission[ " to ensure that multiple permission object IDs are different, are included in param[]

2, at this time, param[:p erson]={:first_name = V,: last_name = V, :p ermission1=>v,:p ermission2 = v ...}

3, <%=person_form. Fields_for "permission[]", permission do |permission_fields| When%>,

param[:p erson]={:first_name = V,: last_name = V, :p ersom=>{:p ermission1=>v,:p ermission2 = v ...} }

Model Code

# models/.person.rb   def permission_attributes=(permission_attributes)    permission|attributes|       permissions. Build (attributes)    end  End  

In order to correspond to the permission[inside the view]

The Create method in the controller

#persons_controller.rbdefNew @person=person.new3. Times {@person. Permissions.build} enddefCreate @person=person.new (params[:p roject)if@person. Save Flash[:notice]="successfully created project."redirect_to Persons_pathElserender:action='New'End End