Open Source Rocks!

ActiveRecord Bulk Insertion of data in rails

noreply@blogger.com (All about programming) — Fri, 14 May 2010 16:17:00 +0000

why we go for bulk insertion?

You take one scenario like there is a loop which insert a record each time it runs. For each and every time it will run a Insert SQL statement for creating the record. You no need to care if it is small number of data. You take millions of record then it will definitely get into performance degradation and slow up your application. So in this case you should have something for bulk insertion.

Solution for Bulk Insert:

When I am looking for bulk insertion of data with activerecord, I got an excellent and efficient way of doing bulk insertion.You may heard of Activerecord::Extensions which gives you the API for bulk insertion.

Step 1:

First install gem

sudo gem install ar-extensions

step 2:

Include this gem in your model

include ar-extensions

Step 3:

Usage : Model.import(columns,values,options)

:columns => array of column identifier
:values => array of values
:options => hash of options

If your model is employee.rb

columns = [emp_id, emp_name, emp_address, emp_dob]
values = [[1, abc, def, '2010-01-01'],[2, foss, texas, '2009-01-01'],[3, xyz, mno, '2008-01-01'],[4, sammy, NYC, '2007-01-01'],......... etc.] (you can add millions of record data)

Employee.import(columns, values)

options:

:validate => true|false default : true. if it is false then it won't use validations

:on_duplicate_key_update => Array|Hash – this tells import to use the associated Array or Hash to update rows where a duplicate key already exists. This is specific MySQL

:ignore => true|false – this tells import to issue a “INSERT IGNORE” when running each SQL statement. This is useful when you are importing mass amounts of records and you don’t care if MySQL finds duplicate entries.

While using this import API you can reduce the data insertion time. I was more surprised with speed when using import API. I hope you also get surprised by using bulk insert.

References - http://www.continuousthinking.com/are/import

Aptitude Package search in Linux

noreply@blogger.com (All about programming) — Fri, 18 Dec 2009 17:50:00 +0000

We can search the packages available in the synaptic package manager without accessing Synaptic Manger GUI mode.

In Terminal

$sudo aptitude search package name

It will gives you the package list which contains your package name. It also tells you whether this package is installed in your machine or not.

Installed Package - starts with 'i'
Not installed Package - starts with 'p'

for eg.,

sudo aptitude search firefox-3
i A firefox-3.0 - safe and easy web browser from Mozilla
i A firefox-3.0-branding - Package that ships the firefox branding
p firefox-3.0-dev - Development files for Mozilla Firefox
p firefox-3.0-dom-inspector - dummy upgrade package for firefox-3.0-dom-inspector -> xulrunner-1.9-dom-inspect
p firefox-3.0-gnome-support - Support for Gnome in Mozilla Firefox
p firefox-3.0-venkman - dummy upgrade package for firefox-3.0-venkman -> xulrunner-1.9-venkman
p firefox-3.1 - dummy upgrade package for firefox-3.1 -> firefox-3.5
p firefox-3.1-branding - dummy upgrade package for firefox-3.1 -> firefox-3.5
p firefox-3.1-dbg - dummy upgrade package for firefox-3.1 -> firefox-3.5
p firefox-3.1-dev - dummy upgrade package for firefox-3.1 -> firefox-3.5
p firefox-3.1-gnome-support - dummy upgrade package for firefox-3.1 -> firefox-3.5
i firefox-3.5 - safe and easy web browser from Mozilla
i A firefox-3.5-branding - Package that ships the firefox branding
p firefox-3.5-dbg - firefox-3.5 debug symbols
p firefox-3.5-dev - Development files for Mozilla Firefox
p firefox-3.5-gnome-support - Support for Gnome in Mozilla Firefox

IBM's Mainframe Machine Dresses up with Linux

noreply@blogger.com (All about programming) — Thu, 17 Dec 2009 13:46:00 +0000

IBM's new system uses IBM's specialty Linux processor and runs either Novell SUSE or Red Hat systems. They are not using mainframe operating system z/OS but includes mainframe management software as well as IBM's z/Virtual Machine system on that machine. So IBM Machines are going to rock with Linux...

Details from
http://www.computerworld.com/s/article/9142007/IBM_s_newest_mainframe_is_all_Linux_

git revert wrong commits

noreply@blogger.com (All about programming) — Sat, 12 Dec 2009 17:58:00 +0000

If you made any mistake in newly committed data then you can revert the git HEAD to previous commit.
For that u have to run the command

git revert --hard

for eg.,

$git revert --hard ab343n78

you can get this hash value in git log file for that you run this command

$git log

This shows you the Commit details in your local machine

Using Jekyll - blog post for static website

noreply@blogger.com (All about programming) — Tue, 08 Dec 2009 12:58:00 +0000

Basically jekyll is the gem which is mainly used for blog aware and static web page generator.
Jekyll follows its own directory structure and we can write it in any markup languages such as HTML, Textile or markdown etc.

#Install Jekyll gem

$ sudo gem install jekyll

#_config.yml

destination: ./_site
auto: false # for auto updation without restarting jekyll server
lsi: true
server_port: 4000 #port number for server
permalink: date #Type of url generated for _posts

The _layout/ folder contains the default layout for website and you can have multiple layouts

The _post/ folder contains the blog post for your website Blog.

The post file name should be in this format "2009-12-8-how-to-post-a-blog-using-jekyll.html"
For reference

In terminal

cd website/ #give project directory
jekyll #It creates the _site/ in your website folder

The _site/ folder has the static web pages with blog posts...

For example:

Layout page i.e default.html has html, head and body tags

default.html:

Inside Body tag contains

{{ content }}

This will replace the content for each page..

The Index.html looks like

index.html

---
layout: default
title: Index Page
---

<------ content for index page ---------->

After runninng the jekyll all this convention are converted as static page.

Rails ActionMailer gmail Configuration using SMTP

noreply@blogger.com (All about programming) — Tue, 06 Oct 2009 12:20:00 +0000

If u have RAILS_VERSION >= 2.3.3 and RUBY VERSION >= 1.8.7

then you no need to install any tls plugin.... Just follow the below steps....

Step 1

You have to add the following Configuration settings in {RAILS_ROOT}/config/environment.rb for Gmail ..

config.action_mailer.raise_delivery_errors = true config.action_mailer.delivery_method = :smtp config.action_mailer.smtp_settings = { :address => "smtp.gmail.com", :port => 587, :domain => "gmail.com", :user_name => "YourmailID@gmail.com", :password => "password123", :authentication => :login, :enable_starttls_auto => true #This line is must to ensure the tls for Gmail } config.action_mailer.default_content_type = "text/html"

Step2
Create mailer for your Project

#Type this in terminal
script/generator mailer
for eg.,
$ script/generator mailer Mailnotifier exists app/models/ create app/views/mailnotifier exists test/unit/ create test/fixtures/mailnotifier create app/models/mailnotifier.rb create test/unit/mailnotifier_test.rb

Step 3
Then you need to generate the mailer method for describing the mail content etc.,

$ script/generate mailer Mailnotifier notifier exists app/models/ exists app/views/mailnotifier exists test/unit/ exists test/fixtures/mailnotifier overwrite app/models/mailnotifier.rb? (enter "h" for help) [Ynaqdh] Y force app/models/mailnotifier.rb overwrite test/unit/mailnotifier_test.rb? (enter "h" for help) [Ynaqdh] Y force test/unit/mailnotifier_test.rb create app/views/mailnotifier/notifier.erb create test/fixtures/mailnotifier/notifier

Step 4
Then your models/Mailnotifier.rb looks like

#models/Mailnotifier.rb class Mailnotifier < ActionMailer::Base def notifier(sent_at = Time.now) subject 'Notifier' recipients 'mailertest@gmail.com' # Give the recipients mailID from 'somemail@gmail.com' sent_on sent_at body :greetings => 'Hi,' end end

Step 5
In views/mailnotifier/notifier.erb file you can format the mail content as you like....

You Type this in your Terminal change directory to your rails application

$ script/console Loading development environment (Rails 2.3.4) >> Mailnotifier.deliver_notifier

This will send You the mail to your recipients address... :)

It Works Cool for me.....

Argument Error (A copy of SectionsController has been removed from the module tree but is still active!)

noreply@blogger.com (All about programming) — Sat, 19 Sep 2009 08:41:00 +0000

U have seen this error frequently in rails 2.3.3.. So what u have do is just call your controller(which is shown in the ArgumentError) explicitly in your dependent controllers.

Add this line on top inside the class:

require "_controller"

This will not throw the following error...

ArgumentError (A copy of SectionsController has been removed from the module tree but is still active!):
app/controllers/sections_controller.rb:61:in `index'
haml (2.2.2) lib/sass/plugin/rails.rb:19:in `process_without_compass'
/usr/lib/ruby/gems/1.8/gems/chriseppstein-compass-0.8.8/lib/compass/app_integration/rails/action_controller.rb:7:in `process'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'

Rendered rescues/_trace (185.0ms)
Rendered rescues/_request_and_response (0.5ms)
Rendering rescues/layout (internal_server_error)

Gem command reference for Rails

noreply@blogger.com (All about programming) — Sat, 19 Sep 2009 08:36:00 +0000

I used this link for gem command reference.... I think this may useful to u...

http://rubygems.org/read/book/1

How to Install the Image_science gems on hardy

noreply@blogger.com (All about programming) — Tue, 30 Jun 2009 11:08:00 +0000

The Gem Image_science is depends on FreeImage and RubyInline.So we have to install these two packages first.

Step : 1

Install FreeImage First from source:


1 sudo apt-get install build-essential
2 cd ~/sources
3 wget http://ftp.cica.es/ubuntu/ubuntu/pool/universe/f/freeimage/freeimage_3.9.3.orig.tar.gz
4 tar -xvf freeimage_3.9.3.orig.tar.gz
5 cd freeimage-3.9.3.repacked/FreeImage
6 make 
7 sudo make install

Step : 2
Install RubyInline as Gem


1 sudo gem install RubyInline -v 3.6.3

Step : 3
Install ImageScience as Gem


1 sudo gem install image_science