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A Tour of State Machines
Episode #392Nov 17, 201293 comments

A Tour of State Machines

Here I show how three popular state machine gems can be used to clean up a list of boolean/datetime fields. I also show a custom solution which keeps track of the history of events. (12 minutes)
Full-Text Search in PostgreSQL
Episode #343Apr 17, 2012131 comments

Full-Text Search in PostgreSQL

Postgres offers full-text searching right out of the box. This episode shows how to write queries from scratch, apply tools like Texticle and pg_search, and optimize performance through indexes. (16 minutes)
Polymorphic Association (revised)
Episode #154May 19, 201299 comments

Polymorphic Association (revised)

A polymorphic association allows a model to belong_to different types of other models. Here I show how to make a single comment model belong to articles, photos, and events. (11 minutes)
ActiveRecord::Relation Walkthrough
Episode #239Nov 07, 201042 comments

ActiveRecord::Relation Walkthrough

The new Active Record query methods in Rails 3 might seem like magic at first. But in this episode I unravel how it works by browsing the Rails 3 source code. (11 minutes)
Active Record Reputation System
Episode #364Jul 09, 2012105 comments

Active Record Reputation System

If you need to calculate an average user's rating or sum up a number of votes, consider using the activerecord-reputation-system gem. Here I will cover the basics and also briefly present a from-scratch solution. (10 minutes)
Contributing to Rails with Git
Episode #113Jun 09, 200836 comments

Contributing to Rails with Git

If you want Rails to behave a certain way, try changing it and submitting a patch. This episode will show how to do exactly this using Git. (11 minutes)
Squeel
Episode #354May 30, 201269 comments

Squeel

Squeel provides a comprehensive DSL for writing SQL queries in Ruby. It is built upon Arel giving you access to many of its powerful features. (9 minutes)
Hacking with Arel
Episode #355May 30, 201270 comments

Hacking with Arel

Here I show a variety of ways to rewrite a long SQL query using only Active Record and Arel. This includes generating scopes dynamically, adding an "or" operator, and adding a powerful "match" method. (15 minutes)
HABTM Checkboxes (revised)
Episode #17Dec 22, 201194 comments

HABTM Checkboxes (revised)

A many-to-many association can be edited through check boxes in a form. Here I show how to do this with a has_many through association complete with clickable labels. (6 minutes)
7 Security Tips
Episode #178Sep 07, 200964 comments

7 Security Tips

Security is important! Here I show seven different security flaws which are common to Rails applications ranging from mass assignment to CSRF protection. (14 minutes)