avoid using prepared statement for fetching the next sequence value

Author: rsim

lib/active_record/connection_adapters/oracle_enhanced_adapter.rb

@@ -531,7 +531,8 @@ def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #
       def next_sequence_value(sequence_name)
         # if sequence_name is set to :autogenerated then it means that primary key will be populated by trigger
         return nil if sequence_name == AUTOGENERATED_SEQUENCE_NAME
-        select_one("SELECT #{quote_table_name(sequence_name)}.NEXTVAL id FROM dual")['id']
+        # call directly connection method to avoid prepared statement which causes fetching of next sequence value twice
+        @connection.select_value("SELECT #{quote_table_name(sequence_name)}.NEXTVAL FROM dual")
       end
 
       def begin_db_transaction #:nodoc:

lib/active_record/connection_adapters/oracle_enhanced_connection.rb

@@ -77,8 +77,6 @@ def describe(name)
         end
       end
 
-      private
-      
       # Returns a record hash with the column names as keys and column values
       # as values.
       def select_one(sql)