21 files changed, 164 insertions, 16 deletions

diff --git a/lib/sql_algebra.rb b/lib/sql_algebra.rb
index b1816844e4..7407dc264b 100644
--- a/lib/sql_algebra.rb
+++ b/lib/sql_algebra.rb
@@ -7,17 +7,21 @@ require 'sql_algebra/relations/table_relation'
 require 'sql_algebra/relations/join_operation'
 require 'sql_algebra/relations/join_relation'
 require 'sql_algebra/relations/attribute'
+require 'sql_algebra/relations/projection_relation'
+require 'sql_algebra/relations/selection_relation'
+require 'sql_algebra/relations/order_relation'
+require 'sql_algebra/relations/range_relation'
 
-require 'sql_algebra/relations/predicates/predicate'
-require 'sql_algebra/relations/predicates/binary_predicate'
-require 'sql_algebra/relations/predicates/equality_predicate'
-require 'sql_algebra/relations/predicates/less_than_predicate'
-require 'sql_algebra/relations/predicates/less_than_or_equal_to_predicate'
-require 'sql_algebra/relations/predicates/greater_than_predicate'
-require 'sql_algebra/relations/predicates/greater_than_or_equal_to_predicate'
-require 'sql_algebra/relations/predicates/range_inclusion_predicate'
-require 'sql_algebra/relations/predicates/relation_inclusion_predicate'
-require 'sql_algebra/relations/predicates/match_predicate'
+require 'sql_algebra/predicates/predicate'
+require 'sql_algebra/predicates/binary_predicate'
+require 'sql_algebra/predicates/equality_predicate'
+require 'sql_algebra/predicates/less_than_predicate'
+require 'sql_algebra/predicates/less_than_or_equal_to_predicate'
+require 'sql_algebra/predicates/greater_than_predicate'
+require 'sql_algebra/predicates/greater_than_or_equal_to_predicate'
+require 'sql_algebra/predicates/range_inclusion_predicate'
+require 'sql_algebra/predicates/relation_inclusion_predicate'
+require 'sql_algebra/predicates/match_predicate'
 
 require 'sql_algebra/extensions/range'
 
diff --git a/lib/sql_algebra/relations/predicates/binary_predicate.rb b/lib/sql_algebra/predicates/binary_predicate.rb
index d7f4cb20e7..d7f4cb20e7 100644
--- a/lib/sql_algebra/relations/predicates/binary_predicate.rb
+++ b/lib/sql_algebra/predicates/binary_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/equality_predicate.rb b/lib/sql_algebra/predicates/equality_predicate.rb
index 2d206e6c12..2d206e6c12 100644
--- a/lib/sql_algebra/relations/predicates/equality_predicate.rb
+++ b/lib/sql_algebra/predicates/equality_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/greater_than_or_equal_to_predicate.rb b/lib/sql_algebra/predicates/greater_than_or_equal_to_predicate.rb
index 49127c312c..49127c312c 100644
--- a/lib/sql_algebra/relations/predicates/greater_than_or_equal_to_predicate.rb
+++ b/lib/sql_algebra/predicates/greater_than_or_equal_to_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/greater_than_predicate.rb b/lib/sql_algebra/predicates/greater_than_predicate.rb
index 03aecaed62..03aecaed62 100644
--- a/lib/sql_algebra/relations/predicates/greater_than_predicate.rb
+++ b/lib/sql_algebra/predicates/greater_than_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/less_than_or_equal_to_predicate.rb b/lib/sql_algebra/predicates/less_than_or_equal_to_predicate.rb
index fee6ea7f35..fee6ea7f35 100644
--- a/lib/sql_algebra/relations/predicates/less_than_or_equal_to_predicate.rb
+++ b/lib/sql_algebra/predicates/less_than_or_equal_to_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/less_than_predicate.rb b/lib/sql_algebra/predicates/less_than_predicate.rb
index 03cbdcf000..03cbdcf000 100644
--- a/lib/sql_algebra/relations/predicates/less_than_predicate.rb
+++ b/lib/sql_algebra/predicates/less_than_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/match_predicate.rb b/lib/sql_algebra/predicates/match_predicate.rb
index 90a13090d4..90a13090d4 100644
--- a/lib/sql_algebra/relations/predicates/match_predicate.rb
+++ b/lib/sql_algebra/predicates/match_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/predicate.rb b/lib/sql_algebra/predicates/predicate.rb
index 4c395a3fdc..4c395a3fdc 100644
--- a/lib/sql_algebra/relations/predicates/predicate.rb
+++ b/lib/sql_algebra/predicates/predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/range_inclusion_predicate.rb b/lib/sql_algebra/predicates/range_inclusion_predicate.rb
index e69de29bb2..e69de29bb2 100644
--- a/lib/sql_algebra/relations/predicates/range_inclusion_predicate.rb
+++ b/lib/sql_algebra/predicates/range_inclusion_predicate.rb
diff --git a/lib/sql_algebra/relations/predicates/relation_inclusion_predicate.rb b/lib/sql_algebra/predicates/relation_inclusion_predicate.rb
index 5881a85d99..5881a85d99 100644
--- a/lib/sql_algebra/relations/predicates/relation_inclusion_predicate.rb
+++ b/lib/sql_algebra/predicates/relation_inclusion_predicate.rb
diff --git a/lib/sql_algebra/relations/order_relation.rb b/lib/sql_algebra/relations/order_relation.rb
new file mode 100644
index 0000000000..8d07c58d64
--- /dev/null
+++ b/lib/sql_algebra/relations/order_relation.rb
@@ -0,0 +1,11 @@
+class OrderRelation < Relation
+  attr_reader :relation, :attributes
+  
+  def initialize(relation, *attributes)
+    @relation, @attributes = relation, attributes
+  end
+  
+  def ==(other)
+    relation == other.relation and attributes.eql?(other.attributes)
+  end
+end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/projection_relation.rb b/lib/sql_algebra/relations/projection_relation.rb
new file mode 100644
index 0000000000..caebfc1b62
--- /dev/null
+++ b/lib/sql_algebra/relations/projection_relation.rb
@@ -0,0 +1,11 @@
+class ProjectionRelation < Relation
+  attr_reader :relation, :attributes
+  
+  def initialize(relation, *attributes)
+    @relation, @attributes = relation, attributes
+  end
+  
+  def ==(other)
+    relation == other.relation and attributes.eql?(other.attributes)
+  end
+end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/range_relation.rb b/lib/sql_algebra/relations/range_relation.rb
new file mode 100644
index 0000000000..fd7e2898fa
--- /dev/null
+++ b/lib/sql_algebra/relations/range_relation.rb
@@ -0,0 +1,11 @@
+class RangeRelation < Relation
+  attr_reader :relation, :range
+  
+  def initialize(relation, range)
+    @relation, @range = relation, range
+  end
+  
+  def ==(other)
+    relation == other.relation and range == other.range
+  end
+end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/selection_relation.rb b/lib/sql_algebra/relations/selection_relation.rb
new file mode 100644
index 0000000000..5654d8de31
--- /dev/null
+++ b/lib/sql_algebra/relations/selection_relation.rb
@@ -0,0 +1,12 @@
+class SelectionRelation < Relation
+  attr_reader :relation, :predicate
+  
+  def initialize(relation, *predicates)
+    @predicate = predicates.shift
+    @relation = predicates.empty?? relation : SelectionRelation.new(relation, *predicates)
+  end
+  
+  def ==(other)
+    relation == other.relation and predicate == other.predicate
+  end
+end
\ No newline at end of file
diff --git a/spec/predicates/binary_predicate_spec.rb b/spec/predicates/binary_predicate_spec.rb
index 1be7dd067d..58e395b08d 100644
--- a/spec/predicates/binary_predicate_spec.rb
+++ b/spec/predicates/binary_predicate_spec.rb
@@ -8,6 +8,12 @@ describe BinaryPredicate do
     @attribute2 = Attribute.new(@relation2, :attribute_name)
   end
   
+  describe BinaryPredicate, '#initialize' do
+    it "requires that both columns come from the same relation" do
+      pending
+    end
+  end
+  
   describe BinaryPredicate, '==' do
     before do
       class ConcreteBinaryPredicate < BinaryPredicate
diff --git a/spec/relations/order_relation_spec.rb b/spec/relations/order_relation_spec.rb
new file mode 100644
index 0000000000..362544d0d1
--- /dev/null
+++ b/spec/relations/order_relation_spec.rb
@@ -0,0 +1,18 @@
+require File.join(File.dirname(__FILE__), '..', 'spec_helper')
+
+describe OrderRelation do
+  before do
+    @relation1 = TableRelation.new(:foo)
+    @relation2 = TableRelation.new(:bar)
+    @attribute1 = @relation1[:foo]
+    @attribute2 = @relation2[:bar]
+  end
+  
+  describe OrderRelation, '==' do
+    it "obtains if the relation and attributes are identical" do
+      OrderRelation.new(@relation1, @attribute1, @attribute2).should == OrderRelation.new(@relation1, @attribute1, @attribute2)
+      OrderRelation.new(@relation1, @attribute1).should_not == OrderRelation.new(@relation2, @attribute1)
+      OrderRelation.new(@relation1, @attribute1, @attribute2).should_not == OrderRelation.new(@relation1, @attribute2, @attribute1)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/relations/projection_relation_spec.rb b/spec/relations/projection_relation_spec.rb
new file mode 100644
index 0000000000..f802a2e293
--- /dev/null
+++ b/spec/relations/projection_relation_spec.rb
@@ -0,0 +1,18 @@
+require File.join(File.dirname(__FILE__), '..', 'spec_helper')
+
+describe ProjectionRelation do
+  before do
+    @relation1 = TableRelation.new(:foo)
+    @relation2 = TableRelation.new(:bar)
+    @attribute1 = @relation1[:foo]
+    @attribute2 = @relation2[:bar]
+  end
+  
+  describe ProjectionRelation, '==' do
+    it "obtains if the relations and attributes are identical" do
+      ProjectionRelation.new(@relation1, @attribute1, @attribute2).should == ProjectionRelation.new(@relation1, @attribute1, @attribute2)
+      ProjectionRelation.new(@relation1, @attribute1).should_not == ProjectionRelation.new(@relation2, @attribute1)
+      ProjectionRelation.new(@relation1, @attribute1).should_not == ProjectionRelation.new(@relation1, @attribute2)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/relations/range_relation_spec.rb b/spec/relations/range_relation_spec.rb
new file mode 100644
index 0000000000..2a1cd1d070
--- /dev/null
+++ b/spec/relations/range_relation_spec.rb
@@ -0,0 +1,18 @@
+require File.join(File.dirname(__FILE__), '..', 'spec_helper')
+
+describe RangeRelation do
+  before do
+    @relation1 = TableRelation.new(:foo)
+    @relation2 = TableRelation.new(:bar)
+    @range1 = 1..2
+    @range2 = Time.now..2.days.from_now
+  end
+  
+  describe RangeRelation, '==' do
+    it "obtains if the relation and range are identical" do
+      RangeRelation.new(@relation1, @range1).should == RangeRelation.new(@relation1, @range1)
+      RangeRelation.new(@relation1, @range1).should_not == RangeRelation.new(@relation2, @range1)
+      RangeRelation.new(@relation1, @range1).should_not == RangeRelation.new(@relation1, @range2)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/relations/relation_spec.rb b/spec/relations/relation_spec.rb
index c482eb4a01..7434bd563b 100644
--- a/spec/relations/relation_spec.rb
+++ b/spec/relations/relation_spec.rb
@@ -12,19 +12,17 @@ describe Relation do
     end
   end
   
-  describe Relation, 'attributes' do
-  end
-  
   describe Relation, '[]' do
     it "manufactures a attribute" do
       @relation1[:id].should be_eql(Attribute.new(@relation1, :id))
     end
     
     it "raises an error if the named attribute is not part of the relation" do
+      pending
     end
   end
   
-  describe Relation, 'include?' do
+  describe Relation, '#include?' do
     before do
       @attribute = Attribute.new(@relation1, :id)
     end
@@ -34,19 +32,32 @@ describe Relation do
     end
   end
   
-  describe Relation, 'project' do
+  describe Relation, '#project' do
     before do
       @attribute1 = Attribute.new(@relation1, :id)
       @attribute2 = Attribute.new(@relation1, :name)
     end
     
     it "only allows projecting attributes in the relation" do
+      pending
     end
     
     it "collapses identical projections" do
+      pending
+    end
+    
+    it "manufactures a projected relation" do
+      @relation1.project(@attribute1, @attribute2).should == ProjectedRelation(@relation1, @attribute1, @attribute2)
     end
   end
   
-  describe Relation, 'select' do
+  describe Relation, '#select' do
+    before do
+      @predicate = EqualityPredicate.new()
+    end
+    
+    it "manufactures a selected relation" do
+      @relation1.select(@attribute1, @attribute2).should == SelectedRelation(@relation1, @attribute1, @attribute2)
+    end
   end 
 end
\ No newline at end of file
diff --git a/spec/relations/selection_relation_spec.rb b/spec/relations/selection_relation_spec.rb
new file mode 100644
index 0000000000..0cfd55449c
--- /dev/null
+++ b/spec/relations/selection_relation_spec.rb
@@ -0,0 +1,28 @@
+require File.join(File.dirname(__FILE__), '..', 'spec_helper')
+
+describe SelectionRelation do
+  before do
+    @relation1 = TableRelation.new(:foo)
+    @relation2 = TableRelation.new(:bar)
+    @predicate1 = EqualityPredicate.new(@relation1[:id], @relation2[:foo_id])
+    @predicate2 = LessThanPredicate.new(@relation1[:age], 2)
+  end
+  
+  describe SelectionRelation, '==' do    
+    it "obtains if both the predicate and the relation are identical" do
+      SelectionRelation.new(@relation1, @predicate1). \
+        should == SelectionRelation.new(@relation1, @predicate1)
+      SelectionRelation.new(@relation1, @predicate1). \
+        should_not == SelectionRelation.new(@relation2, @predicate1)
+      SelectionRelation.new(@relation1, @predicate1). \
+        should_not == SelectionRelation.new(@relation1, @predicate2)
+    end
+  end
+  
+  describe SelectionRelation, '#initialize' do
+    it "manufactures nested selection relations if multiple predicates are provided" do
+      SelectionRelation.new(@relation1, @predicate1, @predicate2). \
+        should == SelectionRelation.new(SelectionRelation.new(@relation1, @predicate2), @predicate1)
+    end
+  end
+end
\ No newline at end of file