initial implementation of cross-engine join

Conflicts:

	lib/arel/engines/memory/relations/array.rb
	lib/arel/engines/sql/primitives.rb

3 files changed, 11 insertions, 1 deletions

diff --git a/lib/arel/engines/sql/engine.rb b/lib/arel/engines/sql/engine.rb
index 0700ae9733..d27d93a5dc 100644
--- a/lib/arel/engines/sql/engine.rb
+++ b/lib/arel/engines/sql/engine.rb
@@ -20,7 +20,9 @@ module Arel
 
         def read(relation)
           # FIXME
-          class << rows = connection.execute(relation.to_sql)
+          rows = connection.select_rows(relation.to_sql)
+          
+          class << rows
             include Enumerable
           end
           
diff --git a/lib/arel/engines/sql/primitives.rb b/lib/arel/engines/sql/primitives.rb
index 9e9143ac0f..22ee19dcf0 100644
--- a/lib/arel/engines/sql/primitives.rb
+++ b/lib/arel/engines/sql/primitives.rb
@@ -4,6 +4,10 @@ module Arel
       original_relation.column_for(self)
     end
 
+    def type_cast(value)
+      root.relation.format(self, value)
+    end
+        
     def format(object)
       object.to_sql(Sql::Attribute.new(self))
     end
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index 2653744149..e842f85ed1 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -16,6 +16,10 @@ module Arel
       end
     end
 
+    def format(attribute, value)
+      attribute.column.type_cast(value)
+    end
+    
     def column_for(attribute)
       has_attribute?(attribute) and columns.detect { |c| c.name == attribute.name.to_s }
     end