db,connection,execute,sql

http://wiki.rubyonrails.org/rails/pages/HowtoQueryTheDatabaseDirectly
http://api.rubyonrails.org/classes/ActiveRecord/Base.html#M001794

<br />require "memcache"<br /><br />CACHE_SERVERS = []<br />rs = ActiveRecord::Base.connection.execute('select * from memcached_servers')<br />rs.each { |r| CACHE_SERVERS << r }<br />CACHE_SERVERS.flatten!<br />CACHE = MemCache.new(GOOKUS_CACHE_SERVERS)<br />

polymphic, comment,db

use polymphic 's benefit
would not need the new table, just change the type could be used for the new model

如果model的相似度高例如 comment , 一個網站裡面很多都可以需要comment

就可以用這個

[forum model]
  has_many :comments, :as => :record

[record model]
  has_many :comments, :as => :record

[comment model]
  belongs_to :record, :polymorphic => true

[comments table]
  create_table "comments", :force => true do |t|
    t.text     "content"
    t.integer  "record_id",   :limit => 11, :null => false
    t.string   "record_type"
  end

Time db

Time#to_s(:db) ignores Time#zone -- example:

>> Time.mktime(2008, 06, 20, 0, 31, 7).to_s(:db)
=> "2008-06-20 00:31:07"
>> Time.utc(2008, 06, 20, 0, 31, 7).to_s(:db)
=> "2008-06-20 00:31:07"