more to_sql

lib/sql_algebra/relations/order_relation.rb

@@ -8,4 +8,12 @@ class OrderRelation < Relation
   def ==(other)
     relation == other.relation and attributes.eql?(other.attributes)
   end
+  
+  def to_sql(builder = SelectBuilder.new)
+    relation.to_sql(builder).call do
+      attributes.each do |attribute|
+        order_by attribute.to_sql(self)
+      end
+    end
+  end
 end

lib/sql_algebra/relations/projection_relation.rb

@@ -8,4 +8,10 @@ class ProjectionRelation < Relation
   def ==(other)
     relation == other.relation and attributes.eql?(other.attributes)
   end
+  
+  def to_sql(builder = SelectBuilder.new)
+    relation.to_sql(builder).call do
+      select attributes.collect { |a| a.to_sql(self) }
+    end
+  end
 end

lib/sql_algebra/relations/range_relation.rb

@@ -8,4 +8,11 @@ class RangeRelation < Relation
   def ==(other)
     relation == other.relation and range == other.range
   end
+  
+  def to_sql(builder = SelectBuilder.new)
+    relation.to_sql(builder).call do
+      limit range.last - range.first + 1
+      offset range.first
+    end
+  end
 end

spec/relations/order_relation_spec.rb

@@ -8,11 +8,22 @@ describe OrderRelation do
     @attribute2 = @relation2[:bar]
   end
   
-  describe OrderRelation, '==' do
+  describe '==' 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
+  
+  describe '#to_s' do
+    it "manufactures sql with an order clause" do
+      OrderRelation.new(@relation1, @attribute1).to_sql.should == SelectBuilder.new do
+        select :*
+        from :foo
+        order_by 'foo.foo'
+      end
+    end
+  end
+  
 end

spec/relations/projection_relation_spec.rb

@@ -8,11 +8,20 @@ describe ProjectionRelation do
     @attribute2 = @relation2[:bar]
   end
   
-  describe ProjectionRelation, '==' do
+  describe '==' 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
+  
+  describe '#to_sql' do
+    it "manufactures sql with a limited select clause" do
+      ProjectionRelation.new(@relation1, @attribute1).to_sql.should == SelectBuilder.new do
+        select 'foo.foo'
+        from :foo
+      end
+    end
+  end
 end

spec/relations/range_relation_spec.rb

@@ -5,14 +5,28 @@ describe RangeRelation do
     @relation1 = TableRelation.new(:foo)
     @relation2 = TableRelation.new(:bar)
     @range1 = 1..2
-    @range2 = Time.now..2.days.from_now
+    @range2 = 4..9
   end
   
-  describe RangeRelation, '==' do
+  describe '==' 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
+  
+  describe '#to_sql' do
+    it "manufactures sql with limit and offset" do
+      range_size = @range2.last - @range2.first + 1
+      range_start = @range2.first
+      RangeRelation.new(@relation1, @range2).to_sql.to_s.should == SelectBuilder.new do
+        select :*
+        from :foo
+        limit range_size
+        offset range_start
+      end.to_s
+    end
+  end
+  
 end