Adding to has_one if text_field != blank or nil - ruby-on-rails

Question

I have a simple has_one relationship setup but I want to add records to Damages table only when the text_field is not blank or nil. Right now it's adding records that are blank or nil to the other table.
My view:
<%= f.fields_for :damage do |builder| %>
<%= builder.label 'Damage' %><br />
<%= builder.text_field :dam_detail %>
<% end %>
Packjob Model:
class Packjob < ActiveRecord::Base
attr_accessible :pj_damage
has_one :damage
accepts_nested_attributes_for :damage
end
Damage Model:
class Damage < ActiveRecord::Base
attr_accessible :dam_detail
belongs_to :packjob
end
How do I allow only non blank or nil values being added?
Is best practice to add logic for this to the helper?
EDIT:
Here's the controller for Packjobs:
class PackjobsController < ApplicationController
# GET /packjobs
# GET /packjobs.json
def index
#packjobs = Packjob.includes(:damage).all
#packers = Packer.find(:all)
#rigs = Rig.find(:all, :order => "rig_type_number")
respond_to do |format|
format.html # index.html.erb
format.json { render json: #packjobs }
end
end
# GET /packjobs/1
# GET /packjobs/1.json
def show
#packjob = Packjob.find(params[:id])
#packers = Packer.find(:all)
respond_to do |format|
format.html # show.html.erb
format.json { render json: #packjob }
end
end
# GET /packjobs/new
# GET /packjobs/new.json
def new
#packjob = Packjob.new
#packers = Packer.find(:all, :conditions => { :p_team => "t" }, :order => "p_name")
#rigs = Rig.find(:all, :conditions => { :rig_status => "t" }, :order => "rig_type_number")
#damage = #packjob.build_damage
##book = #author.build_book
respond_to do |format|
format.html # new.html.erb
format.json { render json: #packjob }
end
end
# GET /packjobs/1/edit
def edit
#packjob = Packjob.find(params[:id])
#packers = Packer.find(:all, :conditions => { :p_team => "t" }, :order => "p_name")
#rigs = Rig.find(:all, :conditions => { :rig_status => "t" }, :order => "rig_type_number")
end
# POST /packjobs
# POST /packjobs.json
def create
#packjob = Packjob.new(params[:packjob])
#packers = Packer.find(:all, :conditions => { :p_team => "t" }, :order => "p_name")
#rigs = Rig.find(:all, :conditions => { :rig_status => "t" }, :order => "rig_type_number")
respond_to do |format|
if #packjob.save
format.html { redirect_to #packjob, notice: 'Packjob was successfully created.' }
format.json { render json: #packjob, status: :created, location: #packjob }
else
format.html { render action: "new" }
format.json { render json: #packjob.errors, status: :unprocessable_entity }
end
end
end
# PUT /packjobs/1
# PUT /packjobs/1.json
def update
#packjob = Packjob.find(params[:id])
#packers = Packer.find(:all, :conditions => { :p_team => "t" }, :order => "p_name")
#rigs = Rig.find(:all, :conditions => { :rig_status => "t" }, :order => "rig_type_number")
respond_to do |format|
if #packjob.update_attributes(params[:packjob])
format.html { redirect_to #packjob, notice: 'Packjob was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: "edit" }
format.json { render json: #packjob.errors, status: :unprocessable_entity }
end
end
end
# DELETE /packjobs/1
# DELETE /packjobs/1.json
def destroy
#packjob = Packjob.find(params[:id])
#packjob.destroy
respond_to do |format|
format.html { redirect_to packjobs_url }
format.json { head :no_content }
end
end
end
Also the I want the packjob to allow for blanks in damage text_field, I just don't want the records added to the Damages table..

Answer 1

This is a job for validations. Specifically, you want two things:
You want your Damage class to validate that :dam_detail is not blank or nil:
class Damage < ActiveRecord::Base
# ... rest of class here ...
validates :dam_detail, :presence => true, :length => { :minimum => 1 }
end
You want your Packjob class to validate that its contained Damage object is valid:
class Packjob < ActiveRecord::Base
# ... rest of class here ...
validates_associated :damage
end
I also recommend modifying your database schema to add the restriction that the dam_detail field cannot be null. See the migrations guide for more info.

Answer 2

Even though its more commonly used for has_many the cocoon gem https://github.com/nathanvda/cocoon is great for this. That gem will allow you to build the relation on the fly from the front end. it will also allow you to destroy the relation too.