Searching for Wildcard Characters in SQL

Been a while - a quick flush...you may have a need to search for the wildcard characters "_" and "%". When that happens you need to know how to escape them. This has slightly different behavior for different database products. MySQL and SQL Server do work the same way, however, if you stick to using the ESCAPE clause.

No Peeking in the Javascript Deque

Another (previous) take on the Javascript Deque with more of a Crockford creation style preventing messing with the Deque's internals. Create one without using new - "var d = deque();", enjoy:

Javascript Deque

Doubly ended queue code is just a whole lot cleaner if you go with dummy head and tail nodes to avoid special cases. I put together this Javascript example: A Javascript array has the methods available (push(), pop(), shift(), unshift()) to be used as a deque but of course being an array you shouldn't be adding and removing from anywhere but the tail end if you need top performance. The following provides for a comparison between my deque and a regular Javascript array for adding and removing items from the head or tail of the data structure.

Items:

array	dequeue
head	tail

My Ubuntu 9.04 Setup for Rails Development

The what, why, and how of bringing up an Ubunto 9.04 box for development...I currently do primarily Ruby on Rails development so that is what you will find here along with the various tools I use to get the job done. The steps are listed below. You can find a file with the apt-get commands I use here. You can also find a file for the gem commands I use here, however, you will have to install rubygems manually before kicking that one off as I have had problems with the Ubuntu package management and rubygems in the past. Here are the full details:

what?	why?	how?
update your system	you just installed	sudo apt-get update && sudo apt-get upgrade
add the terminal to your launcher panel	quick terminal access	applications -> accessories -> right click on terminal, click add launcher to panel
get gtk to use emacs keys	you can't type without this	run gconf-editor, set /desktop/gnome/interface/gtk_key_theme to "Emacs"
change the caps lock to a control	you can't type without this	system -> preferences -> keyboard -> layouts -> layout options -> ctrl key position -> make capslock an additional ctrl
install emacs	you can't work without this	sudo apt-get install emacs
add the emacs to your launcher panel	quick emacs access	applications -> accessories -> right click on emacs, click add launcher to panel
generate a private / public key pair	you are going to use this to connect to github among other	ssh-keygen -t rsa
install git	you can't work without this	sudo apt-get install git-core
set up public key for github	typing passwords repeatedly won't work	follow instructions at github
install subversion	you can't work without this	sudo apt-get install subversion
bring in your bin/ and dotfiles from git	all your common stuff	hmmm, need to expand on this later
install emacs extensions rhtml, rinari, yasnippet, and yasnippets-rails	useful emacs extensions	ummmmm, check them out from github / google code dropping them in your .emacs.d/ directory
install build-essential	every developer needs this at some point to build something	sudo apt-get install build-essential
install ruby development environment	its your dev environment!	sudo apt-get install ruby rdoc ri libopenssl-ruby ruby1.8-dev irb
install mysql	common database for development	sudo apt-get install mysql-server mysql-client libmysqlclient15-dev
install odbc and tds	development against SQL Server	sudo apt-get install unixodbc unixodbc-dev tdsodbc freetds-dev libodbc-ruby1.8
configure your odbcinst.ini for development with dsn-less connections	development against SQL Server	edit your /etc/odbcinst.ini to look like this: [FreeTDS] Description = TDS driver (Sybase/MS SQL) Driver = /usr/lib/odbc/libtdsodbc.so Setup = /usr/lib/odbc/libtdsS.so CPTimeout = CPReuse = FileUsage = 1
install ruby odbc stuff	will need this to work with odbc connections	sudo gem install dbi dbd-odbc
install libxml dev	will need this to install libxml-ruby	sudo apt-get install libxml2-dev
install rubygems	its your ruby packaging system! (not trusting apt-get for this yet, been burned before)	download the latest tgz, unpack, and run sudo ruby setup.rb
symlink gem to gem1.8	you don't want to have to remember to type gem1.8 all the time	cd /usr/bin && ln -s gem1.8 gem
install capistrano	rails deployment nirvana	sudo gem install capistrano
install some of the gems you will be using	rails development	sudo gem install rails mysql libxml-ruby mongrel
install firebug	web development	go get it
install git_remote_branch	makes common git tasks dead simple	sudo gem install git_remote_branch
install the flex sdk	gotta compile flex stuff	go here download the sdk and data visualization components unzip them in a flex_sdk_3 directory and make a flex symlink to that directory
install tofrodos	unix2dos, damn windows line endings	sudo apt-get install tofrodos
install java tools	yes I work with java	sudo apt-get install sun-java6-jdk ant

JavaScript InfoVis Toolkit

The JavaScript InfoVis Toolkit is another example of a library exploiting Canvas technology. I put together a small demo Rails application that uses the toolkit to provide a dynamic tree view of the Rails application directory structure.

Don't Miss Aloha on Rails!

You don't want to miss the Hawaii Ruby On Rails Conference - Waikiki, Oahu, Hawaii - October 5-6 2009. The speaker list is impressive and still growing. The venue is awesome and is only a short (really short!!!) walk from Waikiki beach. The economic downturn is making flights to Hawaii very reasonable right now. This conference is being primarily organized by Seth Ladd, a Honolulu based RoR developer and great co-worker of mine. There is an Aloha On Rail Blog featuring the latest information. The latest post features another great co-worker of mine, Honolulu Hacker Kevin English in a clip on why you should come to Aloha on Rails. Why Aloha on Rails??? mingle with a group of very talented developers gain insights on the latest technologies and techniques re-charge your batteries reward yourself! This is a no brainer - register now!

Rails Bug in *_changed?

UPDATE: The latest rails has fixed this problem but this problem was still present in Rails 2.2.2.

The new dirty methods in Rails show this interesting result:



The above code has position as a nullable integer column. When parameters come in a post via the parameters hash position comes across as a string. For 14 you get the Rails goodness and assigning "14" is not seen as a change - but why not the same thing for 0?

The problem is in the following offending code in vendor/rails/activerecord/lib/active_record/dirty.rb file. I have commented out the problem line (look for the no!!!!...) and added what I believe to be the correct code below it: