问使用Mongoid on Rails 4进行搜索，不仅可以搜索字符串字段，还可以搜索日期范围

EN

class Parent
  include Mongoid::Document
  field :name, type: String
  field :hobby, type: String
  field :born, type: Date

  embeds_many :children
  accepts_nested_attributes_for :children
end

class Child
  include Mongoid::Document
  field :hobby, type: String
  field :name, type: String
  field :born, type: Date

  embedded_in :parent
end

class ParentsController < ApplicationController
  before_action :set_parent, only: [:show, :edit, :update, :destroy]

  # GET /parents
  # GET /parents.json
  def index
    @parents = Parent.all
  end

  # GET /parents/1
  # GET /parents/1.json
  def show
  end

  # GET /parents/new
  def new
    @parent = Parent.new
  end

  # GET /parents/1/edit
  def edit
  end

  # POST /parents
  # POST /parents.json
  def create
    @parent = Parent.new(parent_params)

    respond_to do |format|
      if @parent.save
        format.html { redirect_to @parent, notice: 'Parent was successfully created.' }
        format.json { render action: 'show', status: :created, location: @parent }
      else
        format.html { render action: 'new' }
        format.json { render json: @parent.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /parents/1
  # PATCH/PUT /parents/1.json
  def update
    respond_to do |format|
      if @parent.update_attributes(parent_params)
        format.html { redirect_to @parent, notice: 'Parent was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @parent.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /parents/1
  # DELETE /parents/1.json
  def destroy
    @parent.destroy
    respond_to do |format|
      format.html { redirect_to parents_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_parent
      @parent = Parent.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def parent_params
      params.require(:parent).permit(:name, :hobby, :born)
    end
end

<h1>Listing parents</h1>

<table>
  <thead>
    <tr>
      <th>Name</th>
      <th>Born</th>
      <th></th>
      <th></th>
      <th></th>
    </tr>
  </thead>

  <tbody>
    <% @parents.each do |parent| %>
      <tr>
        <td><%= parent.name %></td>
        <td><%= parent.born %></td>
        <td><%= link_to 'Show', parent %></td>
        <td><%= link_to 'Edit', edit_parent_path(parent) %></td>
        <td><%= link_to 'Destroy', parent, method: :delete, data: { confirm: 'Are you sure?' } %></td>
      </tr>
    <% end %>
  </tbody>
</table>

<br>

<%= link_to 'New Parent', new_parent_path %>