sequel で where 句の書き方

gistfile1.rb

require 'rubygems'
require 'sequel'
require 'pp'

DB = Sequel.sqlite('photo.db')
dataset = DB[:photos]

# どちらでも同じ
# select * from photos where model = 'NIKON D40';
pp dataset.filter(:model => 'NIKON D40').first
pp dataset.where{"model = 'NIKON D40'"}.first

# select date_time_original from photos where model = 'NIKON D40';
pp dataset.filter(:model => 'NIKON D40').first[:date_time_original]