Question

当搜索可以提供许多可选参数（如ID，Zip，City和State）时，如何搜索数据库？这些可以具有值或完全空白。我将如何进行类似的rails查询？

Answer 1

通常的建议是将逻辑移至模型并尽可能保持控制器的精益。过滤方法有不同的方法，第一种方法：

class Record < ActiveRecord::Base
  def self.filter(attributes)
    attributes.select { |k, v| v.present? }.reduce(all) do |scope, (key, value)|
      case key.to_sym
      when :id, :zip # direct search
        scope.where(key => value)
      when :city, :state # regexp search
        scope.where(["#{key} ILIKE ?", "%#{value}%"])
      when :order # order=field-(ASC|DESC)
        attribute, order = value.split("-") 
        scope.order("#{self.table_name}.#{attribute} #{order}")
      else # unknown key (do nothing or raise error, as you prefer to)
        scope
      end 
    end  
  end
end

第二种方法，编写仅使用现有范围的裸filter：

class Record < ActiveRecord::Base
  SUPPORTED_FILTERS = [:id, :city, ...]
  scope :id, ->(value) { where(id: value) }
  scope :city, ->(value) { where(city: "%#{value}%") }
  ...

  def self.filter(attributes)
    attributes.slice(*SUPPORTED_FILTERS).reduce(all) do |scope, (key, value)|
      value.present? ? scope.send(key, value) : scope
    end  
  end
end

对于现在使用ActionController :: Parameters的Rails 5，过滤方法的语法是：

def self.filter(attributes)
  attributes.permit(SUPPORTED_FILTERS).to_hash.reduce(all) do |scope, (key, value)|
    value.present? ? scope.send(key, value) : scope
  end  
end

可以从应用中的任何位置调用模型，因此它们可重复使用且更易于测试。现在控制器看起来很简单：

class RecordsController < ApplicationController::Base
  respond_to :html, :xml

  def index
    @records = Record.filter(params)
  end
end

Answer 2

您可以建立查询：

conditions = {}
conditions[:city] = city unless city.blank?
conditions[:zip] = zip unless zip.blank?
conditions[:state] = state unless state.blank?
Address.find(:all, :conditions => conditions)

Answer 3

http://metautonomo.us/projects/metasearch/就是您所需要的。

= text_field_tag 'search[city_like]', ''
= text_field_tag 'search[zip_equals]', ''
= text_field_tag 'search[state_equals]', ''

然后只是

Record.search(params[:search])

Rails使用可选参数进行搜索？

3 个答案: