Multi-field searches in Rails

I want to do an advanced search form in Rails that has these abilities:

Required

• 5 field_tags where a user can input a search term that searches a开发者_StackOverflow specific field in the table.
• 1 field_tag that searches all fields in the table (DONE).

Preferable

• Be able to specify operators like AND, OR, etc. on these searches.
• Be able to specify more detailed operators like SO does with this, inquestion, etc.

How can I make this happen in practice, especially the 1st bullet point?

I haven't tested this, someone please edit the syntax accordingly, but logically I do not see why it wouldn't work.

app/views/posts/_form.html.erb

<% form_tag(@post, :method => :get) do %>
   <p>
     Search Phrase
         <%= text_field_tag :phrase, params[:phrase] %>
   </p>
   <p>
     <%= radio_button_tag :search_everything, true %>
     Search Everything
   </p>
   <p>
     <%= radio_button_tag :search_everything, false %>
     Advanced Search
   </p>
    <div id="advacned_search">
        <% format_column_names(Post.column_names) do |cn| %>
            <%= check_box_tag "post[column_names][]", cn %> Field 
            <%= check_box_tag cn %><br/>
        <% end %>
    </div>
    <p>
            <%= submit_tag "Search" %>
        </p>
<% end %>

app/helpers/post_helper.rb

    def format_column_names(cns)
        filtered_names = "id" #add the other column names you do not want
        cns.delete_if {|cn| filtered_names.include?(cn) }
        return cns
    end 

app/controllers/posts_controller.rb

    def index
        phrase = params[:phrase]
        if params[:search_everything]
            @posts = Post.find(:all, :conditions => everything_conditions(phrase))
        else
            column_names = params[:column_names]
            @posts = Post.find(:all, :conditions => specific_conditions(column_names, phrase))
        end
    end 

    def everything_conditions(phrase)
        [Post.column_names.map {|cn| "#{cn}=?" }, phrase]
    end

    def specific_conditions(phrase, column_names)
        [column_names.map {|cn| "#{cn}=?" }.join("or "), phrase]
    end 

public/javascripts/post.js#make sure you include jQuery and this file into your view`

jQuery.noConflict();
jQuery(document).ready(function() { 

    $("input[name$='search_everything']").click(function(){
        var value = $(this).val();
        if(value) {
          $("#advanced_search").hide();
        } else {
          $("#advanced_search").show();
        }
     }

})