2 files changed, 8 insertions, 0 deletions
diff --git a/lib/arel/algebra/attributes/attribute.rb b/lib/arel/algebra/attributes/attribute.rb
index 8a7993f284..0ad9382a52 100644
--- a/lib/arel/algebra/attributes/attribute.rb
+++ b/lib/arel/algebra/attributes/attribute.rb
@@ -27,6 +27,10 @@ module Arel
       false
     end
 
+    def eval(row)
+      row[self]
+    end
+
     module Transformations
       def self.included(klass)
         klass.send :alias_method, :eql?, :==
diff --git a/lib/arel/algebra/value.rb b/lib/arel/algebra/value.rb
index 90787fa5ea..70e94e0ad0 100644
--- a/lib/arel/algebra/value.rb
+++ b/lib/arel/algebra/value.rb
@@ -14,6 +14,10 @@ module Arel
         relation == other.relation
     end
 
+    def eval(row)
+      value
+    end
+
     def bind(relation)
       Value.new(value, relation)
     end