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You can get cassandra at cassandra.apache.org and the ruby gem by running: gem install cassandra I did run into a problem with the trift_client gem when installing. If you get a Load Error, run this. sudo chmod 644 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/*.rb sudo chmod 755 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/connection Here are some of the Cassandra commands from the video: #connects to [...]

I had several requests in UserVoice to provide a Many to Many tutorial in Rails. This is a demonstration of how to put together a “has and belongs to many” association and a “has many through” association. This is somewhat basic to Ruby on Rails, but important if you need to associate different models. Download [...]

Emanuele Tozzato gives a brief introduction to Redis, then demonstrates real-life database performance optimization with redis-object and how to manage background jobs using Resque. Bonus content: download the slides from this talk.

Patrick Crowley talks about Trucker, a new gem that makes it easier to migrate legacy data into Rails apps. Bonus content: download the slides from this talk.

Here is what I’ve done to create this application: Use the ‘rails new’ command to create a rails application Set up the Gemfile Configure the Database Install Cucumber Install Rspec Install Devise Install CanCan Install jQuery Configure Devise Download (HD) 84.2 MB Download (iPod & iPhone) 47.4 MB

Quick Ruby Tip: The inject method is useful for aggregating data across a dataset. For example a summation could be done with inject (by aggregating each number into the sum.)

In Rails 3 the non-database functionality of Active Record is extracted out into Active Model. This allows you to cleanly add validations and other features to tableless models.

Learn some advanced techniques regarding named scopes and get an introduction to Arel in this episode.

Machine learning and data mining have long been "black arts" because they require access to expensive computing clusters. Randall Thomas discusses machine learning and the problem spaces it can help solve. Bonus content: download the slides from this talk.

Scott Motte introduces us to the document-oriented database MongoDB and shows how to use MongoDB as an alternative to MySQL and ActiveRecord using the MongoMapper gem. This talk was part of the DjangoSD/SD Ruby mashup meeting. Bonus content: download the slides from this talk.