rails gem系列之ransack

##概要

ransack是一个用来实现检索功能的gem。

github地址: https://github.com/activerecord-hackery/ransack

示例网站：http://ransack-demo.herokuapp.com

##安装

Gemfile

1	gem 'ransack'

然后执行bundle就可以了。

##使用方法

在controller中如下使用,注意参数:q为ransack的固定写法。里面放了view传过来的检索项的值。

def index
  @q = Person.ransack(params[:q])
  @people = @q.result(distinct: true)
end

view中的写法如下。

<%= search_form_for @q do |f| %>

  # Search if the name field contains...
  <%= f.label :name_cont %>
  <%= f.search_field :name_cont %>

  # Search if an associated articles.title starts with...
  <%= f.label :articles_title_start %>
  <%= f.search_field :articles_title_start %>

  # Attributes may be chained. Search multiple attributes for one value...
  <%= f.label :name_or_description_or_email_or_articles_title_cont %>
  <%= f.search_field :name_or_description_or_email_or_articles_title_cont %>

  <%= f.submit %>
<% end %>

##search的写法

eq表示等于

1 2	Item.search(:name_eq => 'test').result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`name` = 'test')"

lt表示小于

1 2	Item.search(:price_lt => 1000).result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`price` < 1000)"

gt表示大于

1 2	Item.search(:price_gt => 1000).result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`price` > 1000)"

in表示sql中的in

1 2	Item.search(:category_id_in => [5,10,15,20]).result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`category_id` IN (5,10,15,20))"

cont表示包含，模糊查询

1 2	Item.search(:name_cont => 'test').result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`name` LIKE '%test%')"

start表示前端一致

1 2	Item.search(:name_start => 'test').result.to_sql # => "SELECT `items`.* FROM `items` WHERE `items`.`name` LIKE 'test%')"

组合用法

Item.search(:name_and_description_cont => 'test').result.to_sql
# => "SELECT `items`.* FROM `items` WHERE (((`items`.`name` LIKE '%test%') AND (`items`.`description` LIKE '%test%')))"
Item.search(:name_or_description_cont => 'test').result.to_sql
# => "SELECT `items`.* FROM `items` WHERE (((`items`.`name` LIKE '%test%') OR (`items`.`description` LIKE '%test%')))"

条件组合
末尾加_all是AND关系，末尾加_any是OR关系

Item.search(:name_cont_all => ['AAA', 'BBB']).result.to_sql
# => "SELECT `items`.* FROM `items` WHERE (((`items`.`name` LIKE '%AAA%') AND (`items`.`name` LIKE '%BBB%')))"
Item.search(:name_cont_any => ['AAA', 'BBB']).result.to_sql
# => "SELECT `items`.* FROM `items` WHERE (((`items`.`name` LIKE '%AAA%') OR (`items`.`name` LIKE '%BBB%')))"