                     ----------  Create or Drop Index  ----------

   "create index" ޥɤϸΥԡɤ夵뤿ˡ°˥ǥå
 Ĥ˻Ѥޤ

 ιʸ

        create [|distinct           |] index [NAME] [on]
                |(PRIMARY, OVERFLOW)|
                |PRIMARY, OVERFLOW  |
                |PRIMARY OVERFLOW   |

                |TABLE (ATTR_NAME {, ATTR_NAME})  |
                |TABLE set ATTR_NAME {, ATTR_NAME}|

    "distinct" ꤵȡʣͤ뤤 null °ͤʤ
 ʤޤ
   "distinct"  PRIMARY 򣱡OVERFLOW 򣰤ˤ뤳ȤƱ̣ޤ
   ޤ"unique" ϡ"distinct" Ʊ̣ޤ

   PRIMARY  OVERFLOW Ǥϳ°ФƵʣͤοꤷޤ
   PRIMARY ˤϼ祤ǥåե˳ǼʣͤοꤷOVERFLOW 
 ˤǥåեγƹԤ˳Ǽʣͤοꤷޤ

   OVERFLOW ǤʤС̵¤˽ʣͤ null ޤ OVERFLOW 
 ʤ PRIMARY ʣͤκȤʤޤ

   "drop index" ޥɤ°饤ǥå˻Ѥޤ

 ιʸ

     drop index | NAME                                           |;
                | NAME [on] TABLE                                |
                | [NAME] [on] |TABLE set ATTR_NAME {,ATTR_NAME}| |
                | [NAME] [on] |TABLE (ATTR_NAME {, ATTR_NAME}) | |
