initial implementation of cross-engine join

Conflicts:

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

7 files changed, 21 insertions, 6 deletions

diff --git a/lib/arel/algebra/relations/row.rb b/lib/arel/algebra/relations/row.rb
index 3731dd9696..e8484944bd 100644
--- a/lib/arel/algebra/relations/row.rb
+++ b/lib/arel/algebra/relations/row.rb
@@ -4,12 +4,13 @@ module Arel
     deriving :==, :initialize
     
     def [](attribute)
-      tuple[relation.position_of(attribute)]
+      attribute.type_cast(tuple[relation.position_of(attribute)])
     end
     
     def slice(*attributes)
       Row.new(relation, attributes.inject([]) do |cheese, attribute|
-        cheese << self[attribute]
+        # FIXME TESTME method chaining
+        cheese << tuple[relation.relation.position_of(attribute)]
         cheese
       end)
     end
diff --git a/lib/arel/engines/memory/relations/array.rb b/lib/arel/engines/memory/relations/array.rb
index 15a3e95e1b..6e2dc29252 100644
--- a/lib/arel/engines/memory/relations/array.rb
+++ b/lib/arel/engines/memory/relations/array.rb
@@ -14,6 +14,10 @@ module Arel
       end
     end
 
+    def format(attribute, value)
+      value
+    end
+    
     def eval
       @array.collect { |r| Row.new(self, r) }
     end
diff --git a/lib/arel/engines/memory/relations/compound.rb b/lib/arel/engines/memory/relations/compound.rb
index 3791fa4622..9e7827dfb3 100644
--- a/lib/arel/engines/memory/relations/compound.rb
+++ b/lib/arel/engines/memory/relations/compound.rb
@@ -3,7 +3,7 @@ module Arel
     delegate :array, :to => :relation
     
     def unoperated_rows
-      relation.eval.collect { |row| row.bind(self) }
+      relation.call.collect { |row| row.bind(self) }
     end
   end
 end
diff --git a/lib/arel/engines/memory/relations/operations.rb b/lib/arel/engines/memory/relations/operations.rb
index e35fbe3234..e0fd2824b3 100644
--- a/lib/arel/engines/memory/relations/operations.rb
+++ b/lib/arel/engines/memory/relations/operations.rb
@@ -47,8 +47,8 @@ module Arel
   class Join < Relation
     def eval
       result = []
-      relation1.eval.each do |row1|
-        relation2.eval.each do |row2|
+      relation1.call.each do |row1|
+        relation2.call.each do |row2|
           combined_row = row1.combine(row2, self)
           if predicates.all? { |p| p.eval(combined_row) }
             result << combined_row
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