title: Oracle 11g : When declaring new TYPE as TABLE, must I add "INDEX BY PLS_INTEGER"?
body: <p>What is the diffecence between adding <code>INDEX BY PLS_INTEGER</code> and not at end of declaration of new table type. Look at this example:</p>
  
  <pre><code>DECLARE
      GC_BULK_LIMIT CONSTANT INTEGER := 500;
      CURSOR CUR_CLIENTS IS SELECT C.ID, C.NAME FROM CLIENTS C;
      TYPE RT_CLIENTS IS TABLE OF CUR_CLIENTS%ROWTYPE;
      -- TYPE RT_CLIENTS IS TABLE OF CUR_CLIENTS%ROWTYPE INDEX BY PLS_INTEGER;
      LT_CLIENTS RT_CLIENTS;
  BEGIN
      OPEN CUR_CLIENTS;
      LOOP
          FETCH CUR_CLIENTS BULK COLLECT INTO LT_CLIENTS LIMIT GC_BULK_LIMIT;
          EXIT WHEN LT_CLIENTS.COUNT = 0;
          FOR I IN 1..LT_CLIENTS.COUNT LOOP
              -- ... SOME LOGIC
          END LOOP;
      END LOOP;
      CLOSE CUR_CLIENTS;
  END;
  </code></pre>