删除表空间（如果不存在）

DECLARE
   v_exists NUMBER;
BEGIN
   SELECT count(*) INTO v_exists FROM dba_tablespaces WHERE tablespace_name = \'hr_test\';
   IF v_exists > 0 THEN
   BEGIN
      EXECUTE IMMEDIATE \'DROP TABLESPACE hr_test INCLUDING CONTENTS AND DATAFILES CASCADE CONSTRAINTS\';
   END;
   END IF;
   EXECUTE IMMEDIATE \'CREATE TABLESPACE hr_RJ DATAFILE \'\'E:\\hr_test_01.dbf\'\' SIZE 16M\';
END;