gather partition table in schema !

Hi all,

   When there are not partition tables, I usually use bellow script to gather statistics of schema:

begin
  dbms_stats.gather_schema_stats(
      ownname          => 'XBANK',
      estimate_percent => dbms_stats.auto_sample_size,
      method_opt       => 'for all columns size auto',
      cascade          => true
   );
end;

   But now, I have some partition tables and can I  use above script with granularity => 'DEFAULT' to gather statistics for schema XBANK ? It look like:

begin
  dbms_stats.gather_schema_stats(
      ownname          => 'XBANK',
      estimate_percent => dbms_stats.auto_sample_size,
      method_opt       => 'for all columns size auto',
      granularity      => 'DEFAULT'
      cascade          => true
   );
end;

   And last question: I was partitioning table A when a session sess_1 accessed and updated data of table A ==> Which errors that I can meet ?