def test_join_two_separate_relations(self):
instring = 'alpha \\theta_join_{a1 = b1} beta;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
right = RelationNode('beta', self.schema)
expected = ThetaJoinNode(left, right, 'a1 = b1')
self.assertEqual(expected, forest[0])
def test_join_two_separate_relations(self):
instring = 'alpha \\natural_join beta;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
right = RelationNode('beta', self.schema)
expected = NaturalJoinNode(left, right)
self.assertEqual(expected, forest[0])
def test_build_when_instring_has_multiple_relations(self):
instring = 'numbers; letters;'
forest = self.build(instring)
self.assertEqual(2, len(forest))
first = RelationNode('numbers', self.schema)
second = RelationNode('letters', self.schema)
self.assertEqual(first, forest[0])
self.assertEqual(second, forest[1])
def test_join_three_separate_relations(self):
instring = 'alpha \\join beta \\join gamma;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
middle = RelationNode('beta', self.schema)
right = RelationNode('gamma', self.schema)
intermediate = CrossJoinNode(left, middle)
expected = CrossJoinNode(intermediate, right)
self.assertEqual(expected, forest[0])
def test_theta_join_with_join(self):
instring = 'alpha \\theta_join_{a1 = b1} beta \\join gamma;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
middle = RelationNode('beta', self.schema)
right = RelationNode('gamma', self.schema)
intermediate = ThetaJoinNode(left, middle, 'a1 = b1')
expected = CrossJoinNode(intermediate, right)
self.assertEqual(expected, forest[0])
def test_natural_join_with_join(self):
instring = 'alpha \\natural_join beta \\join gamma;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
middle = RelationNode('beta', self.schema)
right = RelationNode('gamma', self.schema)
intermediate = NaturalJoinNode(left, middle)
expected = CrossJoinNode(intermediate, right)
self.assertEqual(expected, forest[0])
def test_join_three_separate_relations(self):
instring = 'alpha \\theta_join_{a1 = b1} beta ' \
'\\theta_join_{a1 = b1} gamma;'
forest = self.build(instring)
left = RelationNode('alpha', self.schema)
middle = RelationNode('beta', self.schema)
right = RelationNode('gamma', self.schema)
intermediate = ThetaJoinNode(left, middle, 'a1 = b1')
expected = ThetaJoinNode(intermediate, right, 'a1 = b1')
self.assertEqual(expected, forest[0])
def test_project_with_all_attr(self):
attr = self.schema.get_attributes('magic_wand')
instring = '\\project_{' + ', '.join(attr) + '} magic_wand;'
forest = self.build(instring)
child = RelationNode('magic_wand', self.schema)
expected = ProjectNode(child, attr)
self.assertEqual(expected, forest[0])
def setUp(self):
self.schema = Schema({
'alpha': ['a1'],
'beta': ['b1', 'b2'],
'gamma': ['c1', 'c2', 'c3'],
'twin': ['t1', 't2', 't3'],
'twin_prime': ['t1', 't2', 't3'],
'ambiguous': ['d1', 'd1']
})
self.alpha = RelationNode('alpha', self.schema)
self.beta = RelationNode('beta', self.schema)
self.gamma = RelationNode('gamma', self.schema)
self.twin = RelationNode('twin', self.schema)
self.twin_prime = RelationNode('twin_prime', self.schema)
self.ambiguous = RelationNode('ambiguous', self.schema)
def test_project_with_two_attr(self):
instring = '\project_{owner, wood} magic_wand;'
forest = self.build(instring)
child = RelationNode('magic_wand', self.schema)
expected = ProjectNode(child, ['owner', 'wood'])
self.assertEqual(expected, forest[0])
def test_build_when_instring_is_single_relation(self):
forest = self.build('letters;')
self.assertEqual(1, len(forest))
expected = RelationNode('letters', self.schema)
self.assertEqual(expected, forest[0])
def test_exception_when_join_two_identical_relations(self):
left = RelationNode('alpha', self.schema)
right = RelationNode('alpha', self.schema)
self.assertRaises(RelationReferenceError, NaturalJoinNode, left, right)
def test_attributes_when_name_is_in_schema(self):
expected = AttributeList(self.schema.get_attributes('alpha'),
'alpha').to_list()
node = RelationNode('alpha', self.schema)
self.assertEqual(expected, node.attributes.to_list())
def test_operator_from_init(self):
expected = Operator.relation
actual = RelationNode('alpha', self.schema).operator
self.assertEqual(expected, actual)
