1 files changed, 21 insertions, 0 deletions
diff --git a/lib/arel/predicates.rb b/lib/arel/predicates.rb
index a83bad3c22..051f8abdad 100644
--- a/lib/arel/predicates.rb
+++ b/lib/arel/predicates.rb
@@ -1,5 +1,12 @@
 module Arel
   class Predicate
+    def or(other_predicate)
+      Or.new(self, other_predicate)
+    end
+    
+    def and(other_predicate)
+      And.new(self, other_predicate)
+    end
   end
 
   class Binary < Predicate
@@ -21,6 +28,20 @@ module Arel
     end
     alias_method :to_s, :to_sql
   end
+  
+  class CompoundPredicate < Binary
+    def to_sql(formatter = nil)
+      "(#{operand1.to_sql(formatter)} #{predicate_sql} #{operand2.to_sql(formatter)})"
+    end
+  end
+  
+  class Or < CompoundPredicate
+    def predicate_sql; "OR" end
+  end
+  
+  class And < CompoundPredicate
+    def predicate_sql; "AND" end
+  end
 
   class Equality < Binary
     def ==(other)