使用下拉列表在Ruby on Rails中过滤数据库结果

Question

Respected ppl ...

Im really new with rails so i need your valuable help ...

I have a database view in my db called "graph_hospital_vacant_by_band"

mysql> desc graph_hospital_vacant_by_band;
+-------------------+--------------+------+-----+---------+-------+
| Field             | Type         | Null | Key | Default | Extra |
+-------------------+--------------+------+-----+---------+-------+
| specialisation_id | int(11)      | NO   |     | NULL    |       |
| specialisation    | varchar(255) | YES  |     | NULL    |       |
| nos               | bigint(21)   | NO   |     | 0       |       |
| hospitalband      | varchar(255) | NO   |     | NULL    |       |
+-------------------+--------------+------+-----+---------+-------+
4 rows in set (0.00 sec)

whose model is :

class GraphHospitalVacantByBand < ActiveRecord::Base
 self.table_name = 'graph_hospital_vacant_by_band'
end

and controller is as follows :

class GraphHospitalVacantByBandsController < InheritedResources::Base
end

And view is as follows :

<table class="table table-bordered">
  <thead>
    <tr>
        <th>Specialisation</th>
              <th>No.</th>
        <th>Hospital Band</th>
    </tr>
  </thead>
<tbody>
<% @graph_hospital_vacant_by_bands.each do |graph_hospital_vacant_by_band| %>
  <tr>
             <td><%= graph_hospital_vacant_by_band.specialisation %></td>
             <td><%= graph_hospital_vacant_by_band.nos %></td>
             <td><%= graph_hospital_vacant_by_band.hospitalband %></td>
  </tr>
<% end %>
</tbody>
</table>

Which currently shows this

http://i.stack.imgur.com/v7Jwt.png

I need a dropdown above with the availaible specialisations such that on selecting the particular specialisation the nos,hospitalband for that specialisation is displayed ...

I have looked around and experimented a lot but in vain ....

Im not getting how should i update my model,and controller to handle the passed parameters ....

Thanx very much ...

Sincere Regards -Sky

Answer 1

You can provide filters by using a combination of scopes and where clauses, but it might be easiest to look towards a gem that provides this type of functionality.

Two popular options are Squeel and Ransack . Squeel provides enhancements to how you can search for records using the built-in methods of ActiveRecord. Ransack uses a separate "search form" that you can use to filter the records you're displaying.

If you use either of those gems you'll be updating the controller, adding the search/filter logic and the view to add the search/filter options.

In your controller you'll add

def index
  @q = GraphHospitalVacantByBand.search(params[:q])
  @graph_hospital_vacant_by_bands = @q.result(:distinct => true)
end

In your view you'll need to add a search form:

<%= search_form_for @q do |f| %>
  <%= f.label :specialisation_cont %>
  <%= f.text_field :specialisation_cont %>
  <%= f.label :nos_eq %>
  <%= f.text_field :nos_eq %>
  <%= f.label :hospitalband_cont %>
  <%= f.text_field :hospitalband_cont %>
  <%= f.submit %>
<% end %>

This is a pretty basic search form, providing empty text fields accepting values. For more polish you'd probably want to use selects and provide acceptable values, but this at least gets you started.