ibm_db 2.5.10 adds support for Rails 3.2 and fixes a few minor bugs that have been reported by the community. New features such as Time Travel Queries are supported seamlessly.

The biggest news is the simplified installation process. You now only need to set the DB2′s instance user home, and the gem installation process will take care of determining both which architecture (e.g., 32 vs 64 bit) and libraries to use.

All it really takes now to install ibm_db on a Linux/Unix/Mac box is something along the lines of:

$ sudo -s
$ export IBM_DB_HOME=/home/db2inst1/sqllib
$ gem install ibm_db

Windows users don’t even have to worry about setting up the home directory. It will work both on Windows 32 and 64 bit systems, but unlike with *nix systems, Ruby and ibm_db will run in 32 bit mode only.

To try out DB2 with Ruby/Rails, I recommend you download and install DB2 Express-C for free.

Possibly related posts:

1. Installing the Ruby driver for DB2 on Mac OS X Snow Leopard
2. Installing Ruby on Rails and DB2 on Ubuntu 11.04
3. DB2 support for Ruby/Rails turns 2.0

RubyMotion is not a bridge; it actually generates native applications that are as fast as the ones written in Objective-C . You can check out Ars Technica’s exclusive article for more details on the project and watch the Pragmatic Studio’s 50 minute free screencast about it to get a better idea of how RubyMotion works in practice.

For a limited time you can buy RubyMotion at an early bird discount rate of 25% off. It’s such a productive and affordable solution, that I’m sure it will quickly become popular among Ruby developers who are interested in iOS development and testing, as well as among existing iOS developers.

Many of the questions you may have can likely be found in the FAQ section, but feel free to ask any additional questions here. Enjoy it.

Possibly related posts:

1. Is the Enterprise world Rails ready?
2. Would you use a Mac mini as your development machine?
3. Mobile Development Marketshare Among Hacker News’ Participants

As some of you know, I run a service called Any New Books?, which emails you a list of new books that are related to the categories of your choice each week. For the most part I pulled this list from the weekly staff picks there throughout this past year, just in time for your Christmas shopping.

The books are ordered by their current sale rank on Amazon (from the most popular to the least popular at the moment, with hardcovers first). I hope this page will help you discover a few titles you may have not have noticed yet.

[Mathematics book list]

	The Information: A History, a Theory, a Flood Stores: USA | Canada | Italy | Kindle | UK Kindle By James Gleick ISBN: 0375423729 Publisher: Pantheon Publication date: March 1, 2011 Binding: Hardcover Estimated price: $16.82 Share this book on Twitter |Facebook
	The Art of Computer Programming, Volumes 1-4A Boxed Set Stores: USA | Canada By Donald E. Knuth ISBN: 0321751043 Publisher: Addison-Wesley Professional Publication date: March 13, 2011 Binding: Hardcover Estimated price: $190.47 Share this book on Twitter |Facebook
	Algorithms (4th Edition) Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Robert Sedgewick, Kevin Wayne ISBN: 032157351X Publisher: Addison-Wesley Professional Publication date: March 19, 2011 Binding: Hardcover Estimated price: $59.99 Share this book on Twitter |Facebook
	The Art of Computer Programming, Volume 4A: Combinatorial Algorithms, Part 1 Stores: USA | UK | Canada | Italy By Donald E. Knuth ISBN: 0201038048 Publisher: Addison-Wesley Professional Publication date: January 22, 2011 Binding: Hardcover Estimated price: $53.15 Share this book on Twitter |Facebook
	GPU Computing Gems Emerald Edition Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Editors at Morgan Kaufmann ISBN: 0123849888 Publisher: Morgan Kaufmann Publication date: February 7, 2011 Binding: Hardcover Estimated price: $29.06 Share this book on Twitter |Facebook
	Visualize This: The FlowingData Guide to Design, Visualization, and Statistics Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Nathan Yau ISBN: 0470944889 Publisher: Wiley Publication date: July 20, 2011 Binding: Paperback Estimated price: $20.48 Share this book on Twitter |Facebook
	Programming Android Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Zigurd Mednieks, Laird Dornin, G. Blake Meike, Masumi Nakamura ISBN: 1449389694 Publisher: O’Reilly Media Publication date: August 5, 2011 Binding: Paperback Estimated price: $22.98 Share this book on Twitter |Facebook
	JavaScript: The Definitive Guide: Activate Your Web Pages Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By David Flanagan ISBN: 0596805527 Publisher: O’Reilly Media Publication date: May 10, 2011 Binding: Paperback Estimated price: $27.48 Share this book on Twitter |Facebook
	iOS Programming: The Big Nerd Ranch Guide (2nd Edition) Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Joe Conway, Aaron Hillegass ISBN: 0321773772 Publisher: Addison-Wesley Professional Publication date: July 2, 2011 Binding: Paperback Estimated price: $26.95 Share this book on Twitter |Facebook
	Programming in Objective-C, Third Edition Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Stephen G. Kochan ISBN: 0321711394 Publisher: Addison-Wesley Professional Publication date: June 20, 2011 Binding: Paperback Estimated price: $25.99 Share this book on Twitter |Facebook
	Cocoa Programming for Mac OS X (4th Edition) Stores: USA | Canada | Kindle | UK Kindle By Aaron Hillegass, Adam Preble ISBN: 0321774086 Publisher: Addison-Wesley Professional Publication date: November 19, 2011 Binding: Paperback Estimated price: $27.99 Share this book on Twitter |Facebook
	Introducing HTML5 (2nd Edition) Stores: USA | UK | Canada | Kindle | UK Kindle By Bruce Lawson, Remy Sharp ISBN: 0321784421 Publisher: New Riders Press Publication date: October 28, 2011 Binding: Paperback Estimated price: $14.49 Share this book on Twitter |Facebook
	Programming Python Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Mark Lutz ISBN: 0596158106 Publisher: O’Reilly Media Publication date: January 7, 2011 Binding: Paperback Estimated price: $36.42 Share this book on Twitter |Facebook
	Beginning Android Application Development Stores: USA | UK | Canada | Italy By Wei-Meng Lee ISBN: 1118017110 Publisher: Wrox Publication date: April 19, 2011 Binding: Paperback Estimated price: $15.99 Share this book on Twitter |Facebook
	Agile Web Development with Rails Stores: USA | UK | Canada | Italy By Sam Ruby, Dave Thomas, David Heinemeier Hansson ISBN: 1934356549 Publisher: Pragmatic Bookshelf Publication date: March 31, 2011 Binding: Paperback Estimated price: $22.36 Share this book on Twitter |Facebook
	Eloquent Ruby Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Russ Olsen ISBN: 0321584104 Publisher: Addison-Wesley Professional Publication date: February 21, 2011 Binding: Paperback Estimated price: $24.99 Share this book on Twitter |Facebook
	Matlab, Second Edition: A Practical Introduction to Programming and Problem Solving Stores: USA | UK | Canada | Kindle | UK Kindle By Stormy Attaway ISBN: 0123850819 Publisher: Butterworth-Heinemann Publication date: August 11, 2011 Binding: Paperback Estimated price: $35.44 Share this book on Twitter |Facebook
	Java Performance Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Charlie Hunt, Binu John ISBN: 0137142528 Publisher: Prentice Hall Publication date: October 10, 2011 Binding: Paperback Estimated price: $40.73 Share this book on Twitter |Facebook
	Gamification by Design: Implementing Game Mechanics in Web and Mobile Apps Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Gabe Zichermann, Christopher Cunningham ISBN: 1449397670 Publisher: O’Reilly Media Publication date: August 19, 2011 Binding: Paperback Estimated price: $14.34 Share this book on Twitter |Facebook
	Learn You a Haskell for Great Good!: A Beginner’s Guide Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Miran Lipovaca ISBN: 1593272839 Publisher: No Starch Press Publication date: April 18, 2011 Binding: Paperback Estimated price: $21.55 Share this book on Twitter |Facebook
	Supercharged JavaScript Graphics: with HTML5 canvas, jQuery, and More Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Raffaele Cecco ISBN: 1449393632 Publisher: O’Reilly Media Publication date: August 2, 2011 Binding: Paperback Estimated price: $21.31 Share this book on Twitter |Facebook
	Arduino Robotics Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By John-David Warren, Josh Adams, Harald Molle ISBN: 1430231831 Publisher: Apress Publication date: July 14, 2011 Binding: Paperback Estimated price: $26.38 Share this book on Twitter |Facebook
	HBase: The Definitive Guide Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Lars George ISBN: 1449396100 Publisher: O’Reilly Media Publication date: September 20, 2011 Binding: Paperback Estimated price: $24.99 Share this book on Twitter |Facebook
	The Tangled Web: A Guide to Securing Modern Web Applications Stores: USA | Canada | Kindle | UK Kindle By Michal Zalewski ISBN: 1593273886 Publisher: No Starch Press Publication date: November 26, 2011 Binding: Paperback Estimated price: $26.50 Share this book on Twitter |Facebook
	MongoDB in Action Stores: USA By Kyle Banker ISBN: 1935182870 Publisher: Manning Publications Publication date: December 16, 2011 Binding: Paperback Estimated price: $27.46 Share this book on Twitter |Facebook
	Programming Pig Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Alan Gates ISBN: 1449302645 Publisher: O’Reilly Media Publication date: October 20, 2011 Binding: Paperback Estimated price: $24.99 Share this book on Twitter |Facebook
	The Python Standard Library by Example Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Doug Hellmann ISBN: 0321767349 Publisher: Addison-Wesley Professional Publication date: June 11, 2011 Binding: Paperback Estimated price: $31.49 Share this book on Twitter |Facebook
	The Joy of Clojure: Thinking the Clojure Way Stores: USA | UK | Canada | Italy By Michael Fogus, Chris Houser ISBN: 1935182641 Publisher: Manning Publications Publication date: April 4, 2011 Binding: Paperback Estimated price: $21.99 Share this book on Twitter |Facebook
	Xcode 4 Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Richard Wentk ISBN: 111800759X Publisher: Wiley Publication date: June 28, 2011 Binding: Paperback Estimated price: $19.99 Share this book on Twitter |Facebook
	Programming Amazon EC2 Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Jurg van Vliet, Flavia Paganelli ISBN: 1449393683 Publisher: O’Reilly Media Publication date: March 14, 2011 Binding: Paperback Estimated price: $24.22 Share this book on Twitter |Facebook
	Advanced Mac OS X Programming: The Big Nerd Ranch Guide Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Mark Dalrymple ISBN: 0321706250 Publisher: Addison-Wesley Professional Publication date: August 28, 2011 Binding: Paperback Estimated price: $32.95 Share this book on Twitter |Facebook
	CUDA Application Design and Development Stores: USA | UK | Canada | Kindle | UK Kindle By Rob Farber ISBN: 0123884268 Publisher: Morgan Kaufmann Publication date: November 14, 2011 Binding: Paperback Estimated price: $43.98 Share this book on Twitter |Facebook
	Sinatra: Up and Running Stores: USA | Canada | Kindle | UK Kindle By Alan Harris, Konstantin Haase ISBN: 1449304230 Publisher: O’Reilly Media Publication date: December 1, 2011 Binding: Paperback Estimated price: $15.29 Share this book on Twitter |Facebook
	Management 3.0: Leading Agile Developers, Developing Agile Leaders Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Jurgen Appelo ISBN: 0321712471 Publisher: Addison-Wesley Professional Publication date: January 7, 2011 Binding: Paperback Estimated price: $29.50 Share this book on Twitter |Facebook
	Professional NoSQL Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Shashank Tiwari ISBN: 047094224X Publisher: Wrox Publication date: September 13, 2011 Binding: Paperback Estimated price: $16.99 Share this book on Twitter |Facebook
	Scalability Rules: 50 Principles for Scaling Web Sites Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Martin L. Abbott, Michael T. Fisher ISBN: 0321753887 Publisher: Addison-Wesley Professional Publication date: May 15, 2011 Binding: Paperback Estimated price: $16.96 Share this book on Twitter |Facebook
	Programming Concurrency on the JVM: Mastering Synchronization, STM, and Actors Stores: USA | UK | Canada | Italy By Venkat Subramaniam ISBN: 193435676X Publisher: Pragmatic Bookshelf Publication date: September 2, 2011 Binding: Paperback Estimated price: $19.29 Share this book on Twitter |Facebook
	Learning HTML5 Game Programming: A Hands-on Guide to Building Online Games Using Canvas, SVG, and WebGL Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By James L. Williams ISBN: 0321767365 Publisher: Addison-Wesley Professional Publication date: October 5, 2011 Binding: Paperback Estimated price: $16.54 Share this book on Twitter |Facebook
	Semantic Web for the Working Ontologist, Second Edition: Effective Modeling in RDFS and OWL Stores: USA | UK | Canada | Italy By Dean Allemang, James Hendler ISBN: 0123859654 Publisher: Morgan Kaufmann Publication date: June 3, 2011 Binding: Paperback Estimated price: $38.43 Share this book on Twitter |Facebook
	Brave NUI World: Designing Natural User Interfaces for Touch and Gesture Stores: USA | UK | Canada | Italy By Daniel Wigdor, Dennis Wixon ISBN: 0123822319 Publisher: Morgan Kaufmann Publication date: April 27, 2011 Binding: Paperback Estimated price: $18.49 Share this book on Twitter |Facebook
	Haskell: The Craft of Functional Programming (3rd Edition) Stores: USA | UK | Canada | Italy By Simon Thompson ISBN: 0201882957 Publisher: Addison-Wesley Professional Publication date: October 2, 2011 Binding: Paperback Estimated price: $44.96 Share this book on Twitter |Facebook
	Think Stats Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Allen B. Downey ISBN: 1449307116 Publisher: O’Reilly Media Publication date: July 22, 2011 Binding: Paperback Estimated price: $21.98 Share this book on Twitter |Facebook
	Rails 3 in Action Stores: USA | UK | Canada | Italy By Ryan Bigg, Yehuda Katz ISBN: 1935182277 Publisher: Manning Publications Publication date: September 28, 2011 Binding: Paperback Estimated price: $27.48 Share this book on Twitter |Facebook
	Test Driven Development for Embedded C Stores: USA | UK | Canada | Italy By James W. Grenning ISBN: 193435662X Publisher: Pragmatic Bookshelf Publication date: May 2, 2011 Binding: Paperback Estimated price: $19.37 Share this book on Twitter |Facebook
	MacRuby: The Definitive Guide: Ruby and Cocoa on OS X Stores: USA | UK | Canada | Kindle | UK Kindle By Matt Aimonetti ISBN: 1449380379 Publisher: O’Reilly Media Publication date: November 4, 2011 Binding: Paperback Estimated price: $16.70 Share this book on Twitter |Facebook
	Modern Information Retrieval: The Concepts and Technology behind Search (2nd Edition) Stores: USA | UK | Canada | Italy By Ricardo Baeza-Yates, Berthier Ribeiro-Neto ISBN: 0321416910 Publisher: Addison-Wesley Professional Publication date: February 10, 2011 Binding: Paperback Estimated price: $56.24 Share this book on Twitter |Facebook
	Designing Search: UX Strategies for eCommerce Success Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Greg Nudelman ISBN: 0470942231 Publisher: Wiley Publication date: May 24, 2011 Binding: Paperback Estimated price: $14.99 Share this book on Twitter |Facebook
	Windows Phone 7 Recipes: A Problem-Solution Approach Stores: USA | UK | Canada | Italy | Kindle | UK Kindle By Fabio Claudio Ferracchiati, Emanuele Garofalo ISBN: 1430233710 Publisher: Apress Publication date: May 26, 2011 Binding: Paperback Estimated price: $22.99 Share this book on Twitter |Facebook

No related posts.

Among many other fields, the table Customers includes a column name defined as VARCHAR. name is used to store company names.

One of the requirements for the project was to implement a Google Suggest-like feature. That is, when the user enters a few characters for the customer’s name, they should be prompted, via AJAX, with a list of possible suggestions containing that string (or at least beginning with that string.)

The naive approach would be to use a simple LIKE predicate, to generate queries such as:

SELECT name
FROM   Customers
WHERE  name LIKE '%micro%'
ORDER  BY name

One of the main problems with this approach is performance. Using LIKE this way doesn’t allow us to take advantage of indexes that are defined on the column name.

Unsurprisingly, on a modest server, such a query takes about 25 seconds. A UI that isn’t able to respond for 25 seconds will feel like an eternity for the end user, of course, so a simple query like this obviously cannot be seen as a viable solution.

Enter DB2 Text Search. You may be familiar with other full text search engines such as Ferret, Lucene, or Sphinx. DB2 V9.7.4 ships with an extremely powerful full text search engine that has plenty of useful features, including excellent integration with native XML columns.

Using the free edition of DB2 (DB2 Express-C) which includes Text Search, we were able to implement the autocomplete functionality we were after in a heartbeat, thanks to a query like the following:

SELECT name
FROM   Customers
WHERE  CONTAINS(name, 'micro') = 1
ORDER  BY name

This query was executed in mere fractions of a second for most searches, and behaved exactly as needed. In fact, not only did we match strings that began with the searched token, but also ones that contained it elsewhere (e.g., micro would match both Microsoft and Sun Microsystems.) The results where ordered alphabetically, but could have easily been ordered by relevance via the SCORE function, also available via DB2 Text Search.

As usual, it’s a matter of using the right tool for the right job, and DB2 Text Search was created exactly for these kind of scenarios.

Let’s briefly look at how you can also go about setting up and playing with it on Linux.

Installing DB2 Text Search

To start with, you’ll need to have a 64bit Linux distro, and then follow these simple steps.

Download DB2 Express-C. Make sure you grab the db2exc_974_LNX_x86_64.tar.gz file and not the Light edition.

Next, install DB2 by following these steps (the Installing DB2 section in particular.) Make sure you select a custom installation, and that you select everything including DB2 Text Search (which is not checked by default).

After you’ve started DB2 with db2start via the instance user (e.g., db2inst1,) launch the text search server by running:

db2ts start for text

To enable text search for an existing database, run:

db2ts enable database for text connect to mydb

Next, you’ll need to create a text search index and populate it. For example:

db2ts "create index customer_name for text on customers(name) connect to mydb"
db2ts "update index customer_name for text connect to mydb"

That’s it. From now on you’ll be able to use functions such as CONTAINS to quickly search for your data.

Such a function can also be easily invoked in Rails:

Customer.where("CONTAINS(name, ?) = 1", name)

Or wrapping it a little in a model:

class Customer < ActiveRecord::Base
  # ... 
  def self.search(name, max_res = 10)
    where('CONTAINS(name, ?) = 1', name).
    order('name').
    limit(max_res)
  end
end

Which can then be invoked as follows:

Customer.search("micro")

(Technically we wouldn’t have needed limit, so long as we passed RESULTLIMIT to the CONTAINS function.)

You can read more about DB2 Text Search at the Information Center.

No related posts.

Multiply each item in a list by 2

(1..10).map { |n| n * 2 }

Sum a list of numbers

(1..1000).inject { |sum, n| sum + n }

Or using the (built in) Symbol#to_proc syntax that’s been available since Ruby 1.8.7:

(1..1000).inject(&:+)

Or even just passing a symbol directly:

(1..1000).inject(:+)

Verify if tokens exist in a string

words = ["scala", "akka", "play framework", "sbt", "typesafe"]
tweet = "This is an example tweet talking about scala and sbt."

words.any? { |word| tweet.include?(word) }

Reading a file

file_text = File.read("data.txt")
file_lines = File.readlines("data.txt")

The latter includes “\n” at the end of each element of the array, which can be trimmed by appending .map { |str| str.chop } or by using the alternative version:

File.read("data.txt").split(/\n/)

Happy Birthday

4.times { |n| puts "Happy Birthday #{n==2 ? "dear Tony" : "to You"}" }

Filter a list of numbers

[49, 58, 76, 82, 88, 90].partition { |n| n > 60 }

Fetch and parse an XML web service

require 'open-uri'
require 'hpricot'

results = Hpricot(open("http://search.twitter.com/search.atom?&q=scala"))

This example requires open-uri and hpricot or equivalent libraries (you could use builtin ones if you wish). It’s not too much code, but Scala clearly wins here.

Find minimum (or maximum) in a list

[14, 35, -7, 46, 98].min
[14, 35, -7, 46, 98].max

Parallel Processing

require 'parallel'

Parallel.map(lots_of_data) do |chunk|
  heavy_computation(chunk)
end

Unlike Scala, multicore support is not built-in. It requires parallel or a similar gem.

Sieve of Eratosthenes

The Scala one liner is very clever, but entirely unreadable. A simpler implementation that is no longer a one-liner in Ruby would be:

index = 0
while primes[index]**2 <= primes.last
      prime = primes[index]
      primes = primes.select { |x| x == prime || x % prime != 0 }
      index += 1
end
p primes

This last example is straight from StackOverflow. Not the prettiest code ever, but you get the idea.

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An online compiler, or online IDE is a full software development environment on the web. This allows us programmers to develop from a wider range of machines without any software installations, and to always have our code handy whenever we may need it. There are a wide range of online compiler’s out there today, but Compilr.com is unique since our goal has been to create a fully fledged IDE for developing desktop applications on the web. The idea itself spawned from a combination of wondering what makes an IDE all that it is, knowledge of server side web development languages like PHP and using modern JavaScript libraries to create some really desktop-like user interfaces, and it’s because of the interest in these technologies that we have been able to bring Compilr to where it is today.

2. Why is using an online compiler / online IDE better than programming on my computer?

To develop from a wider range of machines without any software installations, and to always have our code handy whenever you may need it. But some more truly great things can be accomplished from an online IDE such as the ability to develop Windows code from any other OS or a fully online software team communication suite; allowing team members to work on the same code, communicate code changes actively, and instant message each other. Yes, you can accomplish this with desktop software to some extent, but with an online environment you can bring those change notifications instantly opposed to having to look for changes in source control such as svn or git. Online IDEs can also bring a whole new level to social code sharing, like open public projects that can be edited and tested by anyone in the entire world directly in their browser, yet still providing everyone with the version control they need to spot and prevent issues.

3. How did you translate a traditional IDE into a web format, and what stack did you use for the web IDE itself?

Currently we have deployed a lovely combination of Drupal for our CMS features, ExtJS for the bulk of our IDE’s user interface, a custom back-end service to handle code building and a number open source projects.

4. Would you consider Compilr to be complete enough for production use or is there substantial work still to be done?

It all depends on your production, currently we do not have any team integration, but we do support publicly visible projects. So if you’re a one person army, working on a Java, C#, or VB.net desktop application or XNA game, then Compilr might be the right solution for you! In my mind there is always work to be done and this includes: code completion “IntelliSense”, online execution of applications and debugging beyond build warnings and errors, and all those lovely team integration features I mentioned earlier.

5. What is on the horizon for Compilr.com?

Besides all the features we want to add, we are always looking for suggestions, expanding our user base, and looking for way to gain recognition for ourselves and Online IDEs in general, we really believe that online IDEs will provide a lot of value for developers in the future.

6. Are there any technological concerns for maintaining an online compiler? What about security?

Security is definitely a concern for us, during our development we take a lot of care in making sure our access points are as secure as possible, although we are human, and we are capable of making mistakes, so we preform regular backups just in case.

7. As more users come to Compilr, how do you plan to scale the system?

We are constantly optimizing code so we can fit more users on to less machines, with less bandwidth. But we also plan on clustering our users, for example: Group 1 would be mirrored on server A and B while Group 2 would be on server C and D. Completely separating the users data and compilation requirements, besides the common elements required by the CMS front end.

No related posts.

In this brief tutorial I’ll show you how to create a complete Python and Django setup for DB2 on Ubuntu. By following my step-by-step instructions, you’ll be able to install the following components:

• Python
• easy_install
• Django
• DB2 Express-C 9.7.4
• The official Python driver, dbi module, and Django adapter for DB2

Installing Python and easy_install

Technically Python is already installed on Ubuntu, so we don’t have to install it. However, we need the python-dev package in order to build the DB2 driver from source. We’ll also need easy_install which is included in the python-setuptools Ubuntu .deb:

$ sudo apt-get install python-dev python-setuptools

Installing Django

Now that we have easy_install available, we can easily install Django by running:

$ sudo easy_install django

You can verify the installed version by running:

$ python

And then executing the following snippet in the REPL:

>>> import django
>>> django.VERSION
(1, 3, 0, 'final', 0)

At this time, version 1.3.0 should get installed as shown above.

Installing DB2

We can now download and install DB2 Express-C 9.7.4. Download the .tar.gz file to a location that’s convenient for you. Then proceed to unpack it:

$ cd ~/Downloads/
$ tar xvfz db2exc_974_LNX_x86.tar.gz
$ cd expc

We’ll install one required library and then proceed with the setup:

$ sudo apt-get install libaio1
$ sudo ./db2setup

Follow the GUI wizard on screen to continue with the installation. Pay close attention to two steps:

• When prompted select a custom installation, and when choosing the components, select all of them. We’ll need the Application Development Tools in order to build the Python driver later on (and these are unchecked by default).
• When asked if you’d like to create an instance user, go with that option. It greatly simplifies the setup process.

When the setup of DB2 is completed, you should receive a confirmation message informing you about the successful installation

For good measure, add the following line to your ~/.bashrc file:

. /home/db2inst1/sqllib/db2profile

This ensures that even your regular, non-DB2, user will be able to connect and interact with the database.

Installing the Python driver and Django adapter

The last step we need to take is to install the ibm_db Python driver and the ibm_db_dbi module, as well as the Django adapter for DB2. These are all IBM supported, open source releases.

Open a new shell and run:

$ sudo -s
$ export IBM_DB_DIR=/home/db2inst1/sqllib
$ export IBM_DB_LIB=/home/db2inst1/sqllib/lib
$ . /home/db2inst1/sqllib/db2profile
$ easy_install ibm_db ibm_db_django
$ exit

A quick sanity test

To ensure that all is well with your setup, run the following command:

$ django-admin.py startproject db2test
$ cd db2test

Now edit settings.py so ENGINE is set to ibm_db_django, NAME to a database like db2test, USER to db2inst1, PASSWORD to the same password you specified for the db2inst1 user during the installation of DB2. Use localhost for the HOST, and 50000 as the port number:

DATABASES = {
    'default': {
        'ENGINE': 'ibm_db_django',
        'NAME': 'db2test',
        'USER': 'db2inst1',
        'PASSWORD': 'secret',
        'HOST': 'localhost',
        'PORT': '50000',
    }
}

Create the database db2test by running:

$ su - db2inst1
$ db2start
$ db2 create db db2test
$ exit

Depending on your hardware specs, the infrequent operation of creating a database can take a bit of time (e.g., several minutes).

We will now run the actual test:

$ python manage.py test

Unless exceptions are raised during this last step, you should be all set to use Django with DB2.

If you need help

IBM is the only database vendor to officially provide and support its Python driver and Django adapter. While commercial DB2 support is available and relatively inexpensive, your first line of defense is posing your questions in the support forum over at Google. Alternatively, if the question is DB2-specific and not related to Python/Django, you can use the DB2 Express-C forum over at developerWorks instead.

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• Ruby 1.8.7
• Rubygems
• Ruby on Rails
• DB2 Express-C 9.7.4
• The official Ruby driver and Rails adapter for DB2

Installing Ruby

We are going to install Ruby 1.8.7 using the Debian packages that are available in the default repositories:

$ sudo apt-get install ruby-full

Next we’ll build Rubygems from scratch, so as to obtain a recent version and be able to update it to the latest one via the gem system itself:

$ cd /tmp/
$ wget http://production.cf.rubygems.org/rubygems/rubygems-1.7.2.tgz
$ tar xvfz rubygems-1.7.2.tgz
$ cd rubygems-1.7.2
$ sudo ruby setup.rb
$ sudo gem update --system

You can now verify that Rubygems is correctly installed:

$ gem -v
1.8.1

Note: If you plan to have multiple versions of Ruby, you’ll probably want to look into RVM.

Installing Rails

We are not going to install the Rails package that ships with Ubuntu, because this is also quite obsolete at this stage. Instead, we’ll use the newly installed gem command:

$ sudo gem install rails

(Add the --no-rdoc --no-ri flags if you don’t care about the local documentation. This will speed up the installation process.)

You can verify the installed version by running:

$ rails -v
Rails 3.0.7

Installing DB2

We can now download and install DB2 Express-C 9.7.4. Download the .tar.gz installation file to a location that’s convenient for you. Then proceed to unpack it:

$ cd ~/Downloads/
$ tar xvfz db2exc_974_LNX_x86.tar.gz
$ cd expc

We’ll install one required library and then proceed with the setup:

$ sudo apt-get install libaio1
$ sudo ./db2setup

Follow the GUI wizard on screen to continue with the installation. Pay close attention to two steps:

• When prompted select a custom installation, and when choosing the components, select all of them We’ll need the Application Development Tools in order to build the Ruby driver later on. (And these are unchecked by default.)
• When asked if you’d like to create an instance user, go with that option. It greatly simplifies the setup process.

When the setup of DB2 is completed, you should receive a confirmation message informing you about the successful installation.

For good measure, add the following line to your ~/.bashrc file:

. /home/db2inst1/sqllib/db2profile

This ensures that even your regular, non-DB2, user will be able to connect and interact with the database.

Installing the ibm_db gem

The last step we need to take is to install the ibm_db gem, which includes the IBM released (and supported) open source driver for Ruby, as well as the adapter for Rails. You’ll need these in order to use Rails with DB2.

Open a new shell and run:

$ sudo -s
$ export IBM_DB_INCLUDE=/home/db2inst1/sqllib/include
$ export IBM_DB_LIB=/home/db2inst1/sqllib/lib
$ . /home/db2inst1/sqllib/db2profile
$ gem install ibm_db
$ exit

At the time of writing, this installs ibm_db-2.5.6.

A quick sanity test

To ensure that all is well with your setup, run the following command:

$ rails new db2test -d ibm_db
$ cd db2test

Now, edit config/database.yml so that the development section uses the same password you specified for the db2inst1 user during the installation of DB2. Change the database name to something like db2test. The section should look like the example below:

development:
	adapter: ibm_db
	username: db2inst1
	password: secret
	database: db2test

Create the database db2test by running:

$ su - db2inst1
$ db2start
$ db2 create db db2test
$ exit

Depending on your hardware specs, the infrequent operation of creating a database can take quite a long time (e.g., minutes).

We will now install/attach the required gems for this project:

$ bundle install

For the sake of a quick example, we’ll use scaffold to generate some super-basic code. We’ll then run migrations, and the built-in web server:

$ rails g scaffold Subject name:string
$ rake db:migrate
$ rails s

Visit http://localhost:3000/subjects and you should see a scaffold interface you can use to create, edit, show, and destroy subjects, as I’ve done in the screenshot below.

Note: As you develop, you’ll probably want to use a better web server such as mongrel, unicorn, or thin. You can easily do so by editing your Gemfile and installing the gem via bundle.

Getting help

IBM is the only database vendor to officially provide and support its Ruby driver and Rails adapter. While commercial 24/7 DB2 support is certainly available and relatively inexpensive (i.e., cheaper than MySQL), your first line of defense is posing your questions in the support forum over at Rubyforge. Alternatively, if the question is DB2-specific and not related to Ruby or Rails, you can use the DB2 Express-C forum over at developerWorks instead.

Possibly related posts:

1. Installing DB2 9.5 on Ubuntu 7.10
2. Installing Django with PostgreSQL on Ubuntu
3. Installing and configuring DB2 Express-C 9.7 on Ubuntu 9.04 Server

Much as with human languages, programming languages are used to communicate. Interestingly they still involve communication between people, whether other programmers will end up reading/modifying/enhancing your code or you’ll do at a later point in time. Unlike natural languages however, programming languages are unequivocally understood by computers, thanks to the aid of interpreters, compilers, and similar types of software.

Depending on the kind of program you’re trying to write, and in which environment you’re working, you’ll find that some programming languages are better suited than others for certain tasks, even if most common programming languages are labelled as being “general purpose”.

For example, if you want to create iPhone and iPad applications, your best bet would be to use Objective-C. For Android smartphones and tablets, in most cases, you’ll need to become accustomed with Java. If you want to build web applications, you’ll want to learn client-side technologies such as HTML, CSS and JavaScript (of those three only JavaScript is an actual programming language, but the other two are necessary nevertheless). For the server-side of your web application, you’ll probably want to learn a language like PHP, Ruby, or Python (all three have frameworks that will help make most web programming tasks easier and less time consuming), rather than a system programming favorite like C. (And of course, one has to mention SQL if you’re interfacing with a relational database).

So should you start your foray into the world of programming languages with JavaScript? What about Objective-C? SQL? My advice is to avoid starting your programming journey with a language that is tailored to a specific environment. This early in the game, your main objective is to learn how to program – and how to reason like a programmer – rather than learning a specific language. Once you have mastered the fundamental concepts with the aid of a general purpose programming language, you can ease into other languages as the need arises, depending on the type of software you’d like to develop.

This is a profession where most of your skills are developed and honed by actually “doing”. If you grasp the fundamentals of programming outright, you can easily pick up a specific language and framework when you need to build iPad applications or whatever else you’d like to create.

A well-rounded programmer will end up learning several programming languages and tools over the course of their career. That said, if you are just starting out, focus on one language first. While this might seem a tad dull on the surface, the good news is that unless you pick a truly exotic programming language, a lot of what you learn will be applicable to other programming languages as well. Remember that at this stage, above all else, you are learning how to communicate your thoughts in precise statements for other programmers to understand (and for the computer to execute).

For this reason, you can’t really go too wrong with any of the “somewhat mainstream”, general purpose programming languages (e.g., C, Java, C#, Perl, Ruby, Python, or Scheme). That said, particularly if you are learning on your own, I’d advise that you go with a language that will make your learning trek easier. In other words, opt for a programming language that is widely used, well documented, and beginner-friendly. You’re looking for one that isn’t overly bureaucratic, doesn’t require you to manage memory directly, or have a deep understanding of mathematics to get started.

As such, my suggestion would be to start with Python, and use it as a tool to learn the general craft of programming. Learning Python is fun, easy, and useful. You’ll be able to use it for a wide array of projects in several environments (scripting, web, scientific research, etc…).

There are a variety of free tutorials on the web, but if you want a more rigorous/systematic/academic introduction, I highly recommend “Python Programming: An Introduction to Computer Science (2nd Edition)” (USA | UK | Canada).

Once you have learned the fundamentals of programming, have a decent command of the Python language, and have gained some experience with practical Python projects, you should be better armed to evaluate and pick up other languages and frameworks based on the projects you intend to develop or contribute to in the future (Open Source projects are awesome for this purpose).

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1. How did you go from Theoretical Physics to Ruby Programming?

I have a background in computational physics, and I learned Perl and then Python to avoid the pain of C/C++ as much as possible. (The core simulation code for my work was in C/C++ for speed, but I had lots of scripting needs as well, and using C/C++ for scripting would have been horrible.) That led naturally to experimenting with web programming, and I ended up writing my own half-baked web framework in Python. After Rails came out, I switched to Ruby, and haven’t looked back. (I generally prefer Ruby, but Python is also nice. I’ll remain silent on Perl. )

2. There wasn’t a lack of Ruby and Rails books when you started working on the Rails Tutorial. What motivated you to create it?

There were lots of Rails books, but there weren’t any that took the approach I wanted to take, namely, a single substantial sample application with features and pacing carefully chosen for pedagogical purposes. My first book, RailsSpace, filled that niche, but it was out-of-date, and I also perceived an opportunity with the (then-upcoming) release of Rails 3. I figured that a full-length tutorial book aimed at Rails 3 could find a broad audience.

3. What would you say was your biggest challenge in preparing the tutorial?

On a long-term project of this sort, it can be difficult to balance writing with the need to pay the bills. For a while at the beginning, I alternated between doing contract work and writing, and that takes its toll. Not only does contract work take time, but there is a also a big context switch when changing over to writing mode. Doing contract work was necessary given my financial situation at the time, but in the future I expect to be able to focus solely on writing and screencasting.

4. You chose an approach rarely taken by traditional publishers, by producing a free HTML version of the Rails Tutorial, while providing a DRM-free PDF version and supplementary video lessons for a fee. How is the market treating you? Is it an approach that you’d recommend to fellow programmers?

The market response has been great. The free HTML version has attracted lots of referrals and inbound links, which was its main strategic purpose, and it has also generated lots of good karma. Meanwhile, many people are happy to buy the PDF, which is easy to put on an iPad and can be read offline. Readers have also reported that having the PDF gives them a sense of ownership, and they also like knowing that they are supporting the Rails Tutorial project financially.

I have recommended this approach to other programmers (most recently in a talk at the Los Angeles Ruby Conference). Having a free HTML version is a business strategy, not charity, though it does feel good—I’ve gotten email from many readers, especially in poorer countries, thanking me for making the book available for free online.

5. The book is also in print through the excellent Ruby series by Addison-Wesley. Did they reach out to you after the huge success of your online tutorial/video course or was there a plan of world domination all along?

Partnering with a major publisher was part of the initial plan for world domination, but I didn’t think it was strictly necessary. The publisher and I attempted to get a deal in place before I wrote the book, but were unable to come to terms. After I finished the book, we got back in touch and worked out the details of a publication agreement. It’s an unusual arrangement, and I’m thankful to Addison-Wesley for being willing to try it out. Please go out and buy the print edition to reward them for their support of the Ruby community!

6. Do you have any advice for people starting out with Rails (other than reading your book and watching your screencasts, of course)?

Web development is hard, so be prepared for some challenges and occasional frustration. It’s especially good to pick a project you care about; that will help keep you motivated when the going gets tough.

7. If you had a magic wand, what would you change in the Ruby/Rails ecosystem? And how can we make it happen without said magic wand?

I’d make Ruby and Rails installation easier; the barrier to entry in some cases is still forbiddingly high. For example, a while back I spent a couple of hours just getting Ruby to compile after an upgrade to OS X Snow Leopard. (There was a subtle issue related to the location of the readline library headers.) Paradoxically, I think in the early years this may have benefited Rails by insuring that the typical Rails developer was both determined and highly skilled, but the Rails community has matured now to the point where lowering that barrier should be a priority. Happily, Engine Yard has hired the awesome Wayne E. Seguin (best known as the author of Ruby Version Manager, or RVM) to work on exactly this problem. The initial result, the Rails Installer for Windows, looks promising, and I’m excited to see where that project goes from here.

8. What’s next for you?

My O(n) Rails Tutorial workload is minimal right now, which is a good sign, but I have a large O(1) work queue to complete. For example, I’m preparing a free screencast for buyers of the print edition, and I’ve committed to making the HTML book available for translation. Once that work queue cycles down to zero, I’m going to take a little time off, and then I’ll probably start making some more Rails- and Ruby-related products. Interested readers should subscribe to the Rails Tutorial news feed to be notified when future products are available. In addition, anyone who buys the Rails Tutorial PDF/screencast bundle will likely be pleasantly surprised by exclusive coupon codes when the time comes. (Well, they won’t be surprised now, but you get the idea. )

Book giveaway: I will randomly draw one person from among those who share (retweet) this interview on Twitter, and personally ship that person a free printed copy of the Rails 3 Tutorial. All you have to do to be entered in this giveaway is to tweet about this post. I will announce the winner on Friday morning on my twitter account (follow me!) and in the comments below.

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