ruby - update action not working in rails 4 -

when updating form throwing error field unique.

in model

validates :url, presence: true, uniqueness: true, :if => lambda {self.role_id == 2} 

in form

= f.text_field :url, :class => 'form-control' 

in controller

def update respond_to |format|   if @user.update(user_params)     format.html { redirect_to stores_path, notice: 'store updated.' }   else     format.html { render :edit }   end end end 

even if not doing giving me error "this url has been taken". please in advance

i resolved way.

def update respond_to |format|   if @user.update(user_params)     format.html { redirect_to stores_path, notice: 'store updated.' }   else     incoming_url = user.where("id=? , url=?",@user.id,params[:user][:url])     if !incoming_url.blank?       format.html { redirect_to stores_path, notice: 'store updated.' }     end     format.html { render :edit }   end end end