title: list partitioning in oracle tables
body: <p>I have created a table with default partitioning, Now I am adding another partition/subpartition then I am getting oracle error</p>
  
  <pre><code>CREATE TABLE STR_MAINFRAME_DB
  ( 
      CATEGORY         VARCHAR(100) NOT NULL,
      SUBCATEGORY         VARCHAR(100) NOT NULL
  )
  PARTITION BY LIST (CATEGORY)
  SUBPARTITION BY LIST (SUBCATEGORY)
  (
      PARTITION P_DUMMY VALUES (DEFAULT)
      (
          SUBPARTITION S_P_DUMMY VALUES (DEFAULT)  
      ));
  </code></pre>
  
  <p>I am adding one more partition by using below SQL but it is throwing an error.</p>
  
  <pre><code>alter table str_mainframe_db add partition p_1 values ('A');
  
  SQL Error: ORA-14323: cannot add partition when DEFAULT partition exists
  14323. 00000 -  "cannot add partition when DEFAULT partition exists"
  *Cause:    An ADD PARTITION operation cannot be executed when a partition
             with DEFAULT values exists
  </code></pre>
  
  <p>Please help?????????</p>