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require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
module Arel
describe Join do
before do
@relation1 = Table.new(:users)
@relation2 = Table.new(:photos)
@predicate = @relation1[:id].eq(@relation2[:user_id])
end
describe '==' do
before do
@another_predicate = @relation1[:id].eq(1)
@another_relation = Table.new(:cameras)
end
it 'obtains if the two relations and the predicate are identical' do
Join.new("INNER JOIN", @relation1, @relation2, @predicate).should == Join.new("INNER JOIN", @relation1, @relation2, @predicate)
Join.new("INNER JOIN", @relation1, @relation2, @predicate).should_not == Join.new("INNER JOIN", @relation1, @another_relation, @predicate)
Join.new("INNER JOIN", @relation1, @relation2, @predicate).should_not == Join.new("INNER JOIN", @relation1, @relation2, @another_predicate)
end
it 'is commutative on the relations' do
Join.new("INNER JOIN", @relation1, @relation2, @predicate).should == Join.new("INNER JOIN", @relation2, @relation1, @predicate)
end
end
describe 'hashing' do
it 'implements hash equality' do
Join.new("INNER JOIN", @relation1, @relation2, @predicate) \
.should hash_the_same_as(Join.new("INNER JOIN", @relation1, @relation2, @predicate))
end
end
describe '#prefix_for' do
describe 'when the joined relations are simple' do
it "returns the name of the relation containing the attribute" do
Join.new("INNER JOIN", @relation1, @relation2, @predicate).prefix_for(@relation1[:id]) \
.should == @relation1.prefix_for(@relation1[:id])
Join.new("INNER JOIN", @relation1, @relation2, @predicate).prefix_for(@relation2[:id]) \
.should == @relation2.prefix_for(@relation2[:id])
end
end
describe 'when one of the joined relations is an alias' do
before do
@aliased_relation = @relation1.as(:alias)
end
it "returns the alias of the relation containing the attribute" do
Join.new("INNER JOIN", @aliased_relation, @relation2, @predicate).prefix_for(@aliased_relation[:id]) \
.should == @aliased_relation.alias
Join.new("INNER JOIN", @aliased_relation, @relation2, @predicate).prefix_for(@relation2[:id]) \
.should == @relation2.prefix_for(@relation2[:id])
end
end
end
describe '#engine' do
it "delegates to a relation's engine" do
Join.new("INNER JOIN", @relation1, @relation2, @predicate).engine.should == @relation1.engine
end
end
describe 'when joining simple relations' do
describe '#attributes' do
it 'combines the attributes of the two relations' do
join = Join.new("INNER JOIN", @relation1, @relation2, @predicate)
join.attributes.should ==
(@relation1.attributes + @relation2.attributes).collect { |a| a.bind(join) }
end
end
describe '#to_sql' do
it 'manufactures sql joining the two tables on the predicate' do
Join.new("INNER JOIN", @relation1, @relation2, @predicate).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
FROM `users`
INNER JOIN `photos` ON `users`.`id` = `photos`.`user_id`
")
end
it 'manufactures sql joining the two tables, merging any selects' do
Join.new("INNER JOIN", @relation1.select(@relation1[:id].eq(1)),
@relation2.select(@relation2[:id].eq(2)), @predicate).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
FROM `users`
INNER JOIN `photos` ON `users`.`id` = `photos`.`user_id`
WHERE `users`.`id` = 1
AND `photos`.`id` = 2
")
end
end
end
describe 'when joining aggregated relations' do
before do
@aggregation = @relation2 \
.group(@relation2[:user_id]) \
.project(@relation2[:user_id], @relation2[:id].count.as(:cnt)) \
.as('photo_count')
end
describe '#attributes' do
it 'it transforms aggregate expressions into attributes' do
join_with_aggregation = Join.new("INNER JOIN", @relation1, @aggregation, @predicate)
join_with_aggregation.attributes.should ==
(@relation1.attributes + @aggregation.attributes).collect(&:to_attribute).collect { |a| a.bind(join_with_aggregation) }
end
end
describe '#to_sql' do
describe 'with the aggregation on the right' do
it 'manufactures sql joining the left table to a derived table' do
Join.new("INNER JOIN", @relation1, @aggregation, @predicate).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`, `photo_count`.`user_id`, `photo_count`.`cnt`
FROM `users`
INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) AS `photo_count`
ON `users`.`id` = `photo_count`.`user_id`
")
end
end
describe 'with the aggregation on the left' do
it 'manufactures sql joining the right table to a derived table' do
Join.new("INNER JOIN", @aggregation, @relation1, @predicate).to_sql.should be_like("
SELECT `photo_count`.`user_id`, `photo_count`.`cnt`, `users`.`id`, `users`.`name`
FROM (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) AS `photo_count`
INNER JOIN `users`
ON `users`.`id` = `photo_count`.`user_id`
")
end
end
it "keeps selects on the aggregation within the derived table" do
Join.new("INNER JOIN", @relation1, @aggregation.select(@aggregation[:user_id].eq(1)), @predicate).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`, `photo_count`.`user_id`, `photo_count`.`cnt`
FROM `users`
INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` WHERE `photos`.`user_id` = 1 GROUP BY `photos`.`user_id`) AS `photo_count`
ON `users`.`id` = `photo_count`.`user_id`
")
end
end
end
describe 'when joining aliased relations' do
it 'aliases the table and attributes properly' do
aliased_relation = @relation1.as(:alias)
@relation1.join(aliased_relation).on(@relation1[:id].eq(aliased_relation[:id])).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`, `alias`.`id`, `alias`.`name`
FROM `users`
INNER JOIN `users` AS `alias`
ON `users`.`id` = `alias`.`id`
")
end
end
describe 'when joining with a string' do
it "passes the string through to the where clause" do
Join.new("INNER JOIN asdf ON fdsa", @relation1).to_sql.should be_like("
SELECT `users`.`id`, `users`.`name`
FROM `users`
INNER JOIN asdf ON fdsa
")
end
end
end
end
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