join relation qualification

lib/sql_algebra/relations/join_relation.rb

@@ -10,7 +10,12 @@ class JoinRelation < Relation
       ((relation1 == other.relation1 and relation2 == other.relation2) or
       (relation2 == other.relation1 and relation1 == other.relation2))
   end
+
+  def qualify
+    JoinRelation.new(relation1.qualify, relation2.qualify, *predicates.collect(&:qualify))
+  end
   
+  protected
   def joins
     relation1.joins + relation2.joins + [Join.new(relation1, relation2, predicates, join_type)]
   end
@@ -27,6 +32,5 @@ class JoinRelation < Relation
     relation1[name] || relation2[name]
   end
   
-  protected
   delegate :table, :to => :relation1
 end

spec/predicates/binary_predicate_spec.rb

@@ -32,7 +32,7 @@ describe BinaryPredicate do
   end
   
   describe '#qualify' do
-    it "manufactures an equality predicate with qualified attributes" do
+    it "distributes over the predicates and attributes" do
       ConcreteBinaryPredicate.new(@attribute1, @attribute2).qualify. \
         should == ConcreteBinaryPredicate.new(@attribute1.qualify, @attribute2.qualify)
     end

spec/relations/join_relation_spec.rb

@@ -1,6 +1,6 @@
 require File.join(File.dirname(__FILE__), '..', 'spec_helper')
 
-describe 'between two relations' do
+describe JoinRelation do
   before do
     @relation1 = TableRelation.new(:foo)
     @relation2 = TableRelation.new(:bar)
@@ -18,6 +18,13 @@ describe 'between two relations' do
     end
   end
   
+  describe '#qualify' do
+    it 'distributes over the relations and predicates' do
+      JoinRelation.new(@relation1, @relation2, @predicate).qualify. \
+        should == JoinRelation.new(@relation1.qualify, @relation2.qualify, @predicate.qualify)
+    end
+  end
+  
   describe '#to_sql' do
     before do
       @relation1 = @relation1.select(@relation1[:id] == @relation2[:foo_id])

spec/relations/order_relation_spec.rb

@@ -17,7 +17,7 @@ describe OrderRelation do
   end
   
   describe '#qualify' do
-    it "manufactures an order relation with qualified attributes and qualified relation" do
+    it "distributes over the relation and attributes" do
       OrderRelation.new(@relation1, @attribute1).qualify. \
         should == OrderRelation.new(@relation1.qualify, @attribute1.qualify)
     end

spec/relations/projection_relation_spec.rb

@@ -17,7 +17,7 @@ describe ProjectionRelation do
   end
   
   describe '#qualify' do
-    it "manufactures a projection relation with qualified attributes and qualified relation" do
+    it "distributes over teh relation and attributes" do
       ProjectionRelation.new(@relation1, @attribute1).qualify. \
         should == ProjectionRelation.new(@relation1.qualify, @attribute1.qualify)
     end

spec/relations/range_relation_spec.rb

@@ -17,7 +17,7 @@ describe RangeRelation do
   end
   
   describe '#qualify' do
-    it "manufactures a range relation with a qualified relation and a qualified range" do
+    it "distributes over the relation and attributes" do
       pending
     end
   end

spec/relations/rename_relation_spec.rb

@@ -12,10 +12,6 @@ describe RenameRelation do
         should == RenameRelation.new(RenameRelation.new(@relation, @relation[:id] => :humpty), @relation[:name] => :dumpty)
     end
 
-    it "make this test less brittle wrt/ hash order" do
-      pending
-    end
-    
     it "raises an exception if the alias provided is already used" do
       pending
     end
@@ -48,7 +44,7 @@ describe RenameRelation do
   end
   
   describe '#qualify' do
-    it "manufactures a rename relation with an identical attribute and alias, but with a qualified relation" do
+    it "distributes over the relation and renames" do
       RenameRelation.new(@relation, @relation[:id] => :schmid).qualify. \
         should == RenameRelation.new(@relation.qualify, @relation[:id].qualify => :schmid)
     end

spec/relations/selection_relation_spec.rb

@@ -27,7 +27,7 @@ describe SelectionRelation do
   end
   
   describe '#qualify' do
-    it "manufactures a selection relation with qualified predicates and qualified relation" do
+    it "distributes over the relation and predicates" do
       SelectionRelation.new(@relation1, @predicate1).qualify. \
         should == SelectionRelation.new(@relation1.qualify, @predicate1.qualify)
     end