89ffCYQL

1#!/usr/bin/env ruby -Ku
2
3# encoding: utf-8
4
5require 'rubygems'
6require 'dm-core'  # NOTE: dm-core and extlib were installed from git
7require 'pp'
8
9DataMapper::Logger.new($stdout, :debug)
10DataMapper.setup(:default, 'sqlite3::memory:')
11
12class Person
13  include DataMapper::Resource
14
15  property :id,   Serial
16  property :name, String, :nullable => false, :unique => true, :unique_index => true
17end
18
19DataMapper.auto_migrate!
20
21customer1 = Person.create(:name => 'Dan Kubb')
22customer2 = Person.create(:name => 'Alex Kubb')
23
24puts '-' * 80, 'Union:'
25pp Person.all(:name => 'Dan Kubb') | Person.all(:name => 'Alex Kubb')
26pp Person.all(:name => 'Dan Kubb') + Person.all(:name => 'Alex Kubb')
27
28puts '-' * 80, 'Intersection:'
29pp Person.all(:name => 'Dan Kubb') & Person.all(:name => 'Alex Kubb')
30
31puts '-' * 80, 'Difference:'
32pp Person.all(:name => 'Dan Kubb') - Person.all(:name => 'Alex Kubb')
33
34__END__
35
36OUTPUT:
37
38 ~ (0.000169) SELECT sqlite_version(*)
39 ~ (0.000103) DROP TABLE IF EXISTS "people"
40 ~ (0.000025) PRAGMA table_info("people")
41 ~ (0.000733) CREATE TABLE "people" ("id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "name" VARCHAR(50) NOT NULL)
42 ~ (0.000197) CREATE UNIQUE INDEX "unique_people_name" ON "people" ("name")
43 ~ (0.000065) INSERT INTO "people" ("name") VALUES ('Dan Kubb')
44 ~ (0.000062) INSERT INTO "people" ("name") VALUES ('Alex Kubb')
45--------------------------------------------------------------------------------
46Union:
47 ~ (0.000096) SELECT "id", "name" FROM "people" WHERE ("name" = 'Dan Kubb' OR "name" = 'Alex Kubb') ORDER BY "id"
48[#<Person @id=1 @name="Dan Kubb">, #<Person @id=2 @name="Alex Kubb">]
49 ~ (0.000103) SELECT "id", "name" FROM "people" WHERE ("name" = 'Dan Kubb' OR "name" = 'Alex Kubb') ORDER BY "id"
50[#<Person @id=1 @name="Dan Kubb">, #<Person @id=2 @name="Alex Kubb">]
51--------------------------------------------------------------------------------
52Intersection:
53 ~ (0.000061) SELECT "id", "name" FROM "people" WHERE ("name" = 'Dan Kubb' AND "name" = 'Alex Kubb') ORDER BY "id"
54[]
55--------------------------------------------------------------------------------
56Difference:
57 ~ (0.000049) SELECT "id", "name" FROM "people" WHERE ("name" <> 'Alex Kubb' AND "name" = 'Dan Kubb') ORDER BY "id"
58[#<Person @id=1 @name="Dan Kubb">]