什么是深层次结构

What is Deep Structure in ABAP Dictionary
A deep structure is a structure that refers to at least one table type along with data elements, predefined types and structures.

以下就是例子

TYPES: BEGIN OF typ_block,
         bukrs   LIKE rkwa-bukrs,                           "key
         lifnr   LIKE rkwa-lifnr,                           "key
         bwaer   LIKE rkwa-bwaer,                           "key
         it_rkwa LIKE rkwa    OCCURS 1,
         bstat   TYPE c,               
         belnr   LIKE rkwa-belnr,      
         gjahr   LIKE rkwa-gjahr,      
         msgid LIKE sy-msgid,
         msgty LIKE sy-msgty,
         msgno LIKE sy-msgno,
         msgv1 LIKE sy-msgv1,
         msgv2 LIKE sy-msgv2,
         msgv3 LIKE sy-msgv3,
         msgv4 LIKE sy-msgv4,
       END OF typ_block.

什么时候用