Apparantly, Postgresql can’t convert a text column into a boolean, even when passing default values. The standard way of writing the migration didn’t work:
change_column :projects, :status, :boolean, :default=>true

So I started googling and ended up with:
execute "alter table projects ALTER COLUMN status TYPE boolean USING CASE status WHEN '1' THEN true ELSE false END;"

While this line did work, there is a problem with it; it’s not agnostic. It’s written specifically for Postgresql, but may cause issues in other environments.

So, the final, agnostic solution ( thanks Simon! ) uses plain Rails code. Basically we add a temporary column of type :boolean to store the information. After looping over all Project records we have converted all text values to the type boolean. Because we have all information stored in the temporary column, it’s ok to remove the existing status column and rename convert_status to status.

class ConvertStatusToBoolean < ActiveRecord::Migration
  def self.up
    add_column :projects, :convert_status, :boolean, :default => true

    # look up the schema's to be able to re-inspect the Project model
    # http://apidock.com/rails/ActiveRecord/Base/reset_column_information/class
    Project.reset_column_information

    # loop over the collection
    Project.all.each do |p|
        p.convert_status = p.status == '1'
        p.save
    end

    # remove the older status column
    remove_column :projects, :status
    # rename the convert_status to status column
    rename_column :projects,:convert_status,:status
  end

  def self.down
    change_column :projects, :status, :text
  end
end

Handy cheat sheet:
http://dizzy.co.uk/ruby_on_rails/cheatsheets/rails-migrations#execute

Useful info on Apidock:
http://apidock.com/rails/ActiveRecord/Base/reset_column_information/class


// basic authentication
var encoder : Base64Encoder = new Base64Encoder();
encoder.encode(username + ":" password);
// send xml
var header1:URLRequestHeader = new URLRequestHeader("Content-Type", "application/xml");
// authenticate
var header2:URLRequestHeader = new URLRequestHeader("Authorization", "Basic " + encoder.toString());
// accept xml as response
var header3:URLRequestHeader = new URLRequestHeader("Accept","application/xml");

// put your xml in a string: "<ticket><summary>my summary</summary></ticket>"
// generate an XML instance from the string
var xml : XML = new XML( s );
// put the xml in the request instance
request.data = xml;
// use PUT ( could depend on the API you are using, check the docs )
request.method = "PUT";
// use the loader to send the request
var loader : URLLoader = new URLLoader( null );
// wait for the complete event to do other amazing things
loader.addEventListener(Event.COMPLETE,onTicketUpdated,false,0,true);
// fire in the hole!
loader.load( request );
// take a deep breath and wait a sec
// for the complete event to be triggered


Rails Log Visualizer

This is an amazing book. Not only does it handle what it says on the cover, but it also touches advanced use of SVN, common security issues with Rails and so on. 5 out of 5 stars!

Contact.rb ( Model )

...
def name_and_company
@name_and_company = name + " - " + contact.company.name
end
...


Usage ( note the use of :name_and_company )

<%= form.collection_select(:contact_id, @contacts, :id, :name_and_company ) %>


Now, what you normally do is add a third column “id” as primary key. But in this case it can be a recipe for ( a programmer’s ) disaster. The column id would always contain a unique value, but the combination of the two other columns service_id and portfolio_id will not be unique. And thus you could run into a situation where you have multiple rows that hold the same relation:


id | service_id | portfolio_id
-------------------------------
1 | 5 | 3
2 | 2 | 1
3 | 5 | 3


The solution is the use of a compound key: use only two columns and make them both primary key. This will force the relation to be unique, always.


service_id | portfolio_id
--------------------------
5 | 3
2 | 1


I’m suprised I never had to use this before, but I remembered a reference in the “Agile Development with Rails” book.