call the columns hash method

lib/arel/visitors/to_sql.rb

@@ -147,11 +147,11 @@ key on UpdateManager using UpdateManager#key=
 
         return nil unless table_exists? table
 
-        column_cache[table][name]
+        column_cache(table)[name]
       end
 
-      def column_cache
-        @schema_cache.columns_hash
+      def column_cache(table)
+        @schema_cache.columns_hash(table)
       end
 
       def visit_Arel_Nodes_Values o

test/support/fake_record.rb

@@ -3,7 +3,7 @@ module FakeRecord
   end
 
   class Connection
-    attr_reader :tables, :columns_hash
+    attr_reader :tables
     attr_accessor :visitor
 
     def initialize(visitor = nil)
@@ -31,6 +31,10 @@ module FakeRecord
       @visitor = visitor
     end
 
+    def columns_hash table_name
+      @columns_hash[table_name]
+    end
+
     def primary_key name
       @primary_keys[name.to_s]
     end