generated_query.sql

/* generated */
SELECT "user_id", "username", "id", "street" FROM (SELECT "id" AS "user_id", "username" FROM "users") AS "left" NATURAL JOIN "addresses" AS "right"

/* inner join alternative */
SELECT users.id AS user_id, username, addresses.id, street FROM users INNER JOIN addresses ON users.id = addresses.user_id

relation.rb

include Veritas

users     = Relation::Base.new :users, [ Attribute::Integer.new(:id, :key => true), Attribute::String.new(:name) ]
addresses = Relation::Base.new :addresses, [ Attribute::Integer.new(:id, :key => true), Attribute::Integer.new(:user_id), Attribute::String.new(:street) ]

relation = users.rename(:id => :user_id).join(addresses)

SQL::Generator::Relation.visit(relation).to_sql