Joy of Think

Android has built-in sqlite database support. But it needs special table in database before it can be used:

• A table named android_metadata which only have one TEXT columm: locale.
• A record in this table, value is en_US.

Here are samples of SQL:
CREATE TABLE if not exists android_metadata (locale TEXT)
insert into android_metadata(locale) value 'en_US'

百般恳求，医生终于大发慈悲，帮着拍了几张照片。

Link: http://blog.aizatto.com/2007/05/21/activerecord-without-rails/

The basic idea is to using following method to connect database.

require "active_record"
ActiveRecord::Base.establish_connection(params)


The params must be a hash or object.

Based on this method, user can use yaml to load configure just like rails do:


dbconfig = YAML::load(File.open('database.yml'))
ActiveRecord::Base.establish_connection(dbconfig)


SQLite sample

development:
  adapter: sqlite3
  database: db/development.db
  pool: 5
  timeout: 5000

Migration


ActiveRecord::Migrator.up('db/migrate')
class CreateLogTables < ActiveRecord::Migration
def self.up
create_table :accounts do |t|
t.integer :account_id
end

end
end


Using ActiveRecord


class Account < ActiveRecord::Base
has_many :sessions
end

class Session < ActiveRecord::Base
belongs_to :user
has_many :actions
end

class Action < ActiveRecord::Base
belongs_to :session
end


Logger


ActiveRecord::Base.logger = Logger.new(File.open('log/database.log', 'a'))
ActiveRecord::Base.colorize_logging = false


Link: https://help.ubuntu.com/community/Kernel/Compile

Install package and source

sudo apt-get install fakeroot kernel-wedge build-essential makedumpfile kernel-package

Get source

sudo apt-get build-dep --no-install-recommends linux-image-$(uname -r)
apt-get source linux-image-$(uname -r)

Link: http://www.ruby-forum.com/topic/73148

Here is a very useful document about net::http performance. It introduces a idea that small buffer used in rbuf_fill causes interior performance of net/http. And he also introduce a workaround. The general idea is override the default behavior. Here are code:

class OverrideInternetMessageIO < Net::InternetMessageIO
  def rbuf_fill
    timeout(@read_timeout) {
      @rbuf << @socket.sysread(65536)
    }
  end
end

class NewHTTP < Net::HTTP
  def NewHTTP.socket_type
     OverrideInternetMessageIO
  end
end