如何查询rails方式？ Rails 3.2

Question

模型之间的关系列表：

class ErrorScope  < ActiveRecord::Base
  belongs_to :server
  has_many :scope_to_fixflow_map
  attr_accessible :id, :server_id, :error_codes, :scoping_method, :priority, :error_codes_is_wildcard_match
  serialize :error_codes
  .....
end

class ScopeToFixflowMap < ActiveRecord::Base
  belongs_to :error_scope
  attr_accessible :id, :server_id, :error_scope_id, :path, :fixflow_class_name
  ......
end

class Server < ActiveRecord::Base
  has_many :error_scopes 
  ......
end

schema.rb

  create_table "error_scopes", :force => true do |t|
    t.integer "server_id",                     :limit => 8,                    :null => false
    t.text    "error_codes",                                                   :null => false
    t.text    "scoping_method"
    t.integer "priority",                                                      :null => false
    t.boolean "error_codes_is_wildcard_match",              :default => false
  end

  create_table "scope_to_fixflow_maps", :force => true do |t|
    t.integer "server_id",          :limit => 8, :null => false
    t.integer "error_scope_id",     :limit => 8, :null => false
    t.string  "path"
    t.string  "fixflow_class_name",              :null => false
  end

现在我有一个 sql 查询，它给出了我想要的输出：

SELECT fixflow_class_name 
FROM error_scopes s
join scope_to_fixflow_maps m on s.id=m.error_scope_id
join servers serv on serv.id=s.server_id
where error_codes regexp 'error_scope_test'
and path = 'x'
and assettag = 'y'

到目前为止我尝试了什么。有效

ErrorScope.where("error_codes like ?", "%error_scope_test\n%").select {|tag| tag.server.assettag == "y"}[0].scope_to_fixflow_map.select {|y| y.path == "x"}[0].fixflow_class_name

使用联接

ErrorScope.joins(:server, :scope_to_fixflow_map).where("error_codes LIKE ?", "%error_scope_test%").select {|tag| tag.server.assettag == "y"}[0].scope_to_fixflow_map.select {|y| y.path == "x"}[0].fixflow_class_name

我确定一定有更好的方法来执行此查询？？

Answer 1

不是 rails 的方式，而是快速而肮脏的方式：

ActiveRecord::Base.execute("SELECT fixflow_class_name 
FROM error_scopes s
join scope_to_fixflow_maps m on s.id=m.error_scope_id
join servers serv on serv.id=s.server_id
where error_codes regexp 'error_scope_test'
and path = 'x'
and assettag = 'y'")

Returns 返回您可以使用的哈希数组

Answer 2

像这样：

ErrorScope.joins(:server, :scope_to_fixflow_map)
.where("error_codes LIKE ?", "%error_scope_test%") 
.where("servers.assettag='y'")
.where("scope_to_fixflow_maps.path='x'")
.select("scope_to_fixflow_maps.fixflow_class_name")

如何查询rails方式？ Rails 3.2

How to query rails way ? Rails 3.2

ruby

mysql

sql

activerecord

ruby-on-rails-3