Postgres accent insensitive LIKE search in Rails 3.1 on Heroku

Question

How can I modify a where/like condition on a search query in Rails:

find(:all, :conditions => [\"lower(name) LIKE ?\", \"%#{search.downcase}%\"])

Answer 1

First of all, you install postgresql-contrib. Then you connect to your DB and execute:

CREATE EXTENSION unaccent;

to enable the extension for your DB.

Depending on your language, you might need to create a new rule file (in my case greek.rules, located in /usr/share/postgresql/9.1/tsearch_data), or just append to the existing unaccent.rules (quite straightforward).

In case you create your own .rules file, you need to make it default:

ALTER TEXT SEARCH DICTIONARY unaccent (RULES='greek');

This change is persistent, so you need not redo it.

The next step would be to add a method to a model to make use of this function.

One simple solution would be defining a function in the model. For instance:

class Model < ActiveRecord::Base
    [...]
    def self.unaccent(column,value)
        a=self.where('unaccent(?) LIKE ?', column, "%value%")
        a
    end
    [...]
end

Then, I can simply invoke:

Model.unaccent("name","text")

Invoking the same command without the model definition would be as plain as:

Model.where('unaccent(name) LIKE ?', "%text%"

Note: The above example has been tested and works for postgres9.1, Rails 4.0, Ruby 2.0.

UPDATE INFO
Fixed potential SQLi backdoor thanks to @Henrik N's feedback