Some Quick Tips

1. Removing a column from a table in SQLite

There’s no straight forward way in SQLite so you need to copy the contents into a new table drop and recreate the table and put the data back in. In short, its a big mess. Thankfully rails manages that for us.

rails generate migration RemoveUserIdFromProjects user_id:integer

rake db:migrate

2. Creating static data

I needed some static data in my application, specifically project statuses, but I wanted to have an ability to maintain them in the database so we could add/ remove them as needed. The way I did it was through Fixtures. All you need to do is:

a. Inside the db/migrate directory, create a directory called init_data. Create a file called <tablename>.yml inside init_data. Copy the format from model yml inside the test directory of the project. Oh by the way, you would need to have a model for the table, obviously.

b. Create a file called <a number>_load_<table name>.rb inside db/migrate. Adjust the number so that the file appears at the end of the directory listing by name. The following is what I created for my model (called State). I guess you can use it as is – just find and replace State with your model name

require 'active_record/fixtures'
class LoadStates < ActiveRecord::Migration

def self.up

down()
 directory = File.join(File.dirname(__FILE__), "init_data")

Fixtures.create_fixtures(directory, "states")

end

def self.down

State.delete_all

end

end

Thats it – now run rake db:migrate and it will load all data as defined in the fixture YML.
3. Adding a URL to an existing controller

e.g. I needed to add a URL /projects/load to call method “load()” in my projects controller. Add the following in routes.rb before the resource definition:

match 'projects/load' => 'projects#load'