Several Rails migration methods accept index: true as an option to create an index. In some cases (like #add_column), this option is silently discarded. Know what you are doing, or use #add_index instead.

Example

Consider the following ...

When searching for text in a MySQL table, you have two choices:

• The LIKE operator
• [FULLTEXT](http://dev.mysql.com/doc/refman/5.0/en/fulltext-boolean.html...

Development environment setup

Rails Composer
: Basically a comprehensive Rails Template. Prepares your development environment and lets you select web server, template engine, unit and integration t...

This is a small example on how you can check if your Postgres index can be used by a specific query in you Rails application. For more complex execution plans it might still be a good idea to use the same path of proof.

1. Identify the...

PostgreSQL has partial indexes. With a partial index you tell Postgres to only index rows matching a given query.

Some uses cases for a partial index:

• You want a uniqueness index, but...

validates_uniqueness_of is not sufficient to ensure the uniqueness of a value. The reason for this is that in production, multiple worker processes can cause race conditions:

1. Two concurrent requests try to create a user with the same name (a...

It is common in Rails 3.0 applications that you want to provide default views for a group of controllers. Let’s say you have a bunch of controllers inside the Admin namespace and you would like each action to fallback to a default template. So if ...

Find conditions for scopes can be given either as an array (:conditions => ['state = ?', 'draft']) or a hash (:conditions => { 'state' => 'draft' }). The later is nicer to read, but has horrible security implications in some versions of Ru...

Learn everything you need to know about Scaling your Rails app through 13 informative Screencasts produced by Gregg Pollack with the support of New Relic.

You might find that your Passenger ignores all RailsSomething directives in the vhost for your new Rails 3 application. The culprit is a file config.ru which makes Passenger consider your application a Rack (non-Rails) application.

To fix thi...