rob-murray

columns_that_make_record_distinct = [:some_id, :another_name]
distinct_ids = Model.select("MIN(id) as id").group(columns_that_make_record_distinct).map(&:id)

duplicate_records = Model.where.not(id: distinct_ids)

rob-murray

// Useful for when you've just installed a new version of Ruby and need to install your common/favourite gems
//
gem install bundler pry awesome_print foreman rails ferver london-bike-hire-cli benchmark-ips rubocop

rob-murray

# a method that is a simple hash acting as a cache to remote service, db call, etc
#
def a_cache
  @a_cache ||= Hash.new do |cache, reference|
    cache[reference] = Service.fetch(reference)
  end
end

# usage
# a_cache[reference]

rob-murray

say_with_time "Doing an update" do
  execute %q{UPDATE somethings SET a_col = 'foo' WHERE other_col IN ('bar', 'foobar')}
end

# or

execute <<-SQL
  CREATE UNIQUE INDEX foobars_name_lower_idx ON foobars (LOWER(name));
SQL

rob-murray

rob-murray

class Money
  STANDARD_VAT_RATE = 0.2.freeze

  attr_reader :amount

  def self.in_pence(amount_in_pence)
    new(amount_in_pence)
  end

  def initialize(amount)

rob-murray

class UnionFind

  attr_accessor :nodes, :sizes

  def initialize(num)
    self.nodes = []
    self.sizes = []

    num.times do |n|
      self.nodes[n] = n

rob-murray

rob-murray

boot2docker start
export etc
docker images
docker build -t robmurray/name:tag . # build current
docker run -P --name foo robmurray/name:tag # test
docker kill # above
docker push robmurray/name:tag
# switch to docker-machine
eval "$(docker-machine env {machine})"
docker stop current # stop current container # downtime :(

rob-murray

# app/models/blog_post.rb
class BlogPost < Post
  has_many :comments
end