ABAP-数据引用

*&---------------------------------------------------------------------*
*& Report  ZRICO_TEST3
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*
report zrico_test3.

data:ztb type string,
     zfd type string.
data:gt_tab like table of mara with header line.

start-of-selection.
  ztb = 'MARA'.
  zfd = 'MATNR'.

  field-symbols:<zs> type mara,
                <zl> type any,
                <z1> type any.
  data:dref type ref to data.

  create data dref type (ztb).
  assign dref->* to <zs>.

  assign component zfd of structure <zs> to <zl>.

  types:begin of t_struct,            "*定義一個結構*
          col1 type i,
          col2 type i,
        end of t_struct.
  data: dref1 type ref to data,       "*定義兩個數據引用*
        dref2 type ref to data.
  field-symbols: <fs1> type t_struct, "*定義兩個字段符號*
                 <fs2> type i.
  create data dref1 type t_struct.    "*利用數據引用，動態創建對象*
  assign dref1->* to <fs1>.           "*因為數據引用只是地址，不能直接操作使用，需要把它分配給字段符號*
  <fs1>-col1 = .                     "*賦值給組件字段*
  <fs1>-col2 = .
  dref2 = dref1.                      "*把一個數據引用賦值給另一個數據引用*
  assign dref2->* to <fs1>.           "*爲了要輸出，需要把數據應用分配給字段符號*
  write: / 'DREF2',<fs1>-col1, <fs1>-col2. "*可以直接輸出了*
  assign dref2->* to <fs2> casting.   "*把結構變量分配給整形字段符號，因此要進行隱式數據類型轉換*
  write / <fs2>.                      "*輸出<FS2>字段符號變量內容*
  get reference of <fs1>-col2 into dref2. "*取得變量的數據應用，給DREF2*
  assign dref2->* to <fs2>.           "*分配變量給字段符號<FS2>*
  write / <fs2>.