内表定义和关于针对内表的操作

内表定义的语法：
TYPES: itbl TYPE TABLE WITH UNIQUE KEY FIELD.

示例:
TYPES: BEGIN OF ADDRESS,
      STREET(20) TYPE C,
      CITY(20) TYPE C,
END OF ADDRESS.

DATA: BEGIN OF COMPANY,
     NAME(20) TYPE C,
     ADDRESSES TYPE ADDRESS,
END OF COMPANY.

DATA itbl_standand_Company LIKE STANDARD TABLE OF COMPANY
       WITH UNIQUE KEY NAME.

DATA itbl_hashed_Company LIKE HASHED TABLE OF COMPANY
        WITH UNIQUE KEY NAME.

DATA itbl_company_sorted LIKE SORTED TABLE OF COMPANY
       WITH UNIQUE KEY NAME.