Syntax to create a dependent relation?

In my controller I have this:

  def new     load_entity     @location =     @site = @location.build_site

    respond_to do |format|       format.html # new.html.erb       format.xml { render :xml => @location }     end   end

  # GET /locations/1/edit   def edit     load_entity     @location = @entity.locations(params[:id])   end

  # POST /locations   # POST /locations.xml   def create     load_entity     @site = @location.build_site(params[:site])     @location =[:location].datebalk!)

When I return from my form I have this in params{}

{"user"=>{"userid"=>"authuser", "user_id"=>13466, "user_name"=>"A. N. Authorized-User"}, "entity_id"=>"1", "commit"=>"Create", "authenticity_token"=>"a99e941c6191c6a0897165549bb2606328472187", "site"=>{"site_postal_code"=>" ", "site_municipality"=>"Hamilton", "site_street_number"=>" ", "site_region"=>"Ontario", "site_name"=>" ", "site_country_code"=>"CA", "site_building_floor"=>" ", "site_street_name"=>"", "site_building_name"=>" ", "site_building_unit_number"=>" "}, "location"=>{"location_description"=>" ", "superseded_after__dteblk"=>"", "effective_from__dteblk"=>"", "location_type"=>"MAIN", "effective_from"=>"", "superseded_after"=>""}}

What is the correct syntax to get the hash "site" and the hash "location" contained within the hash "params"?