How to show edit button only for a record and save data to database from edit form in rails

I am displaying all the records from db in the form of HTML table along with edit button. On, click of edit button it redirects to edit view which will display the additional columns.

Here, I was showing save button in edit form for all the rows/records. Is there a way to prevent so that I can just show to the one I selected in index form.

Also, after updating the fields how do I save the record and redirect to index view.

Please find the code snippets below:

metrics_controller.rb:

class MetricsController < ApplicationController
  def index
    @metricAll = Metric.all
  end

  def show
    @metric = Metric.find(params[:id])
  end

  def edit
    @metric = Metric.find(params[:id])
    @metricAll = Metric.all
  end

  def create
    @metric = Metric.new(post_params)
    if(@metric.save)
      redirect_to @metric
    else
      render 'new'
    end
  end

  def update
    @metric = Metric.find(params[:id])
    if(@metric.update_attributes(post_params))
      redirect_to @metric
    else
      render 'edit'
    end
  end

  private def post_params
    params.require(:metric).permit(:Metric, :WI, :Value, :UT, :Score, :IsValid, :UserName, :Comments)
  end
end

edit.html.rb:

<%= form_for :metrics_controller, url: metric_path(@metric), method: :patch do |f| %>
  <table id="metrics">
    <thead>
    <tr id="AllMetricColumnNames">
      <th id="Metric"><div>Metric</th>
      <th id="WI">WI</th>
      <th id="Value">Value</th>
      <th id="UT">UT</th>
      <th id="Score">Score</th>
      <th id="IsValid">IsValid</th>
      <th id="UserName">UserName</th>
      <th id="Comments">Comments</th>
      <th id="EditColumn">Edit</th>
    </tr>
    </thead>
    <% @metricAll.each do |data| %>
      <tr id="AllMetricValues">
        <td id="Value"><%= data.Metric %></td>
        <td id="WI"><%= data.WI %></td>
        <td id="Value"><%= data.Value %></td>
        <td id="UT"><%= data.UT %></td>
        <td id="Score"><%= data.Score %></td>
        <td><%= f.select :IsValid, options_for_select(['True', 'False']), :include_blank => true, :class => 'chosen-select', :required => true, value: data.IsValid  %></td>
        <td id="UserName"><%= data.UserName %></td>
        <td id="Comments"><%= f.text_field :Comments, value: data.Comments %></td>
        <td id="SaveButton"><%= f.submit "Save" %></td>
    <% end %>
    </tr>
  </table>
<% end %>

Screenshot: