ruby on rails - UnknownAttributeError in Controller -

with of @sasha created nested form treatments in patients:

now error:

unknownattributeerror in patientscontroller#update  unknown attribute: treatment 

my patients update controller looks this:

def update   @patient = patient.find(params[:id])    respond_to |format|     if @patient.update_attributes(params[:patient])       format.html { redirect_to @patient, notice: 'patient updated.' }       format.json { head :no_content }     else       format.html { render action: "edit" }       format.json { render json: @patient.errors, status: :unprocessable_entity }     end   end end 

and form this:

<%= form_for @patient |f| %>   <%= f.fields_for ([@patient, @patient.treatments.build]) |tf| %>     <%= render 'treatment_form', form: tf  %>   <% end %>   <%= f.fields_for ([@patient, @patient.treatments.build]) |tf| %>     <%= render 'treatment_form', form: tf  %>   <% end %>   <%= f.submit %> <% end %> 

so have no clue have add patients controller?

i changed code @jimlim recomended, same error:

 activerecord::unknownattributeerror in patientscontroller#update   unknown attribute: treatment  {"utf8"=>"✓", "_method"=>"put", "authenticity_token"=>"opus9mmk3guiv20nkw5oapufyjvow49h+mmxy37o0r0=",  "patient"=>{"treatment"=>{"category_id"=>"9",  "content"=>"dsfsdf", "day"=>"2013-07-21"}}, "commit"=>"update patient",  "id"=>"9"} 

the parameters include treatment key not attribute in patient model. if case, need to

1. change form such key treatments instead of treatment, and
2. add #accepts_nested_attribute_for in patient model.

for example,

<%= f.fields_for :treatments, @patient.treatments.build |tf| %>   <%= render 'treatment_form', form: tf  %> <% end %>  class patient   accepts_nested_attributes_for :treatments end 

a more detailed explanation available in documentation fields_for.