moved sql related code to its own engine area

Conflicts:

	lib/arel/engine.rb
	lib/arel/extensions/object.rb
	lib/arel/predicates.rb
	lib/arel/primitives/attribute.rb
	lib/arel/primitives/expression.rb
	lib/arel/primitives/value.rb
	lib/arel/relations/operations/join.rb
	lib/arel/relations/relation.rb
	lib/arel/relations/utilities/externalization.rb
	lib/arel/relations/utilities/nil.rb
	lib/arel/relations/writes/delete.rb
	lib/arel/relations/writes/insert.rb
	lib/arel/relations/writes/update.rb
	spec/arel/unit/relations/skip_spec.rb
	spec/arel/unit/relations/take_spec.rb
	spec/spec_helper.rb

1 files changed, 41 insertions, 0 deletions

diff --git a/lib/arel/engines/sql/engine.rb b/lib/arel/engines/sql/engine.rb
new file mode 100644
index 0000000000..e5d1a8b0ca
--- /dev/null
+++ b/lib/arel/engines/sql/engine.rb
@@ -0,0 +1,41 @@
+module Arel
+  module Sql
+    class Engine
+      def initialize(ar = nil)
+        @ar = ar
+      end
+
+      def connection
+        @ar.connection
+      end
+
+      def method_missing(method, *args, &block)
+        @ar.connection.send(method, *args, &block)
+      end
+
+      module CRUD
+        def create(relation)
+          connection.insert(relation.to_sql)
+        end
+
+        def read(relation)
+          results = connection.execute(relation.to_sql)
+          rows = []
+          results.each do |row|
+            rows << attributes.zip(row).to_hash
+          end
+          rows
+        end
+
+        def update(relation)
+          connection.update(relation.to_sql)
+        end
+
+        def delete(relation)
+          connection.delete(relation.to_sql)
+        end
+      end
+      include CRUD
+    end
+  end
+end
\ No newline at end of file