1 files changed, 15 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index d8c92d0ad3..f3fba9a3a9 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -12,6 +12,7 @@ require 'active_record/connection_adapters/abstract/connection_pool'
 require 'active_record/connection_adapters/abstract/connection_specification'
 require 'active_record/connection_adapters/abstract/query_cache'
 require 'active_record/connection_adapters/abstract/database_limits'
+require 'active_record/result'
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
@@ -40,7 +41,7 @@ module ActiveRecord
         @active = nil
         @connection, @logger = connection, logger
         @query_cache_enabled = false
-        @query_cache = {}
+        @query_cache = Hash.new { |h,sql| h[sql] = {} }
         @instrumenter = ActiveSupport::Notifications.instrumenter
       end
 
@@ -97,6 +98,12 @@ module ActiveRecord
         quote_column_name(name)
       end
 
+      # Returns a bind substitution value given a +column+ and list of current
+      # +binds+
+      def substitute_for(column, binds)
+        Arel.sql '?'
+      end
+
       # REFERENTIAL INTEGRITY ====================================
 
       # Override to turn off referential integrity while executing <tt>&block</tt>.
@@ -135,6 +142,13 @@ module ActiveRecord
         # this should be overridden by concrete adapters
       end
 
+      ###
+      # Clear any caching the database adapter may be doing, for example
+      # clearing the prepared statement cache.  This is database specific.
+      def clear_cache!
+        # this should be overridden by concrete adapters
+      end
+
       # Returns true if its required to reload the connection between requests for development mode.
       # This is not the case for Ruby/MySQL and it's not necessary for any adapters except SQLite.
       def requires_reloading?