ABAP Basic Concept (2)

1. ABAP Basic Concept (2) • 運算子 • 控制式與迴圈 • IF, CASE, DO… ENDDO • SQL指令 • Subroutines • Call by value, value and result, reference • Event Block • Initialization, Start-of-Selection, At Line-Selection

2. 1. 運算子 • 比較運算子= , <> , < , <= , > , >= • 算數運算子+ , - , * , /, mod (餘數) • 邏輯運算子AND , OR

3. 2. 控制式與迴圈 • IF子句 IF <Logical Expression> . <Statements>.ELSEIF <Logical Expression> . <Statements>.ELSE . <Statements>.ENDIF . • CASE子句 CASE < variable > .WHEN 'value1' .<Statements>.WHEN 'value2' OR 'value3' .<Statements>. WHEN OTHERS . <Statements>. ENDCASE .

4. 控制式與迴圈 (Cont.) • DO…ENDDO子句 DO 整數變數 TIMES. ENDDO. • 範例： DATA X TYPE I. DATA N TYPE I. X = 1. N = 5. DO N TIMES. WRITE: / X. X = X + 1. ENDDO.

5. 3. SQL 指令 • SELECT < result > 哪些欄位FROM < table > 從哪個tableINTO < destination > 複製到哪WHERE < condition >. 條件 • SELECT SINGLE * 從database中只挑選一列符合條件的資料 • INTO指令與CORRESPONDING FIELDS OF…連用

6. SQL 指令 (Cont.) • SELECT…… ENDSELECT • 為一種迴圈結構，其中的程式段會被反覆執行直到資料庫讀取結束 • 範例：印出zplayer table中所有球員的姓名 SELECT pno pname FROM zplayer INTO CORRESPONDING FIELDS OF wa_player. WRITE: /20 wa_player-pname. ENDSELECT.

7. 練習D • 印出TABLE內容 (程式名稱zyy**_ex_d) • 使用SELECT …ENDSELECT，印出zyy**_EMP該Table中，CLASS欄位為A1的所有記錄。 • 判斷是否有記錄，若無則印出There is no record in the table；若有資料則印出Table has at least one record。

8. 練習D參考解答 REPORT zyyTC_EX_D . TABLES zyyTC_EMP. SELECT * FROM zyyTC_EMP WHERE CLASS = 'A1'. WRITE : / zyyTC_EMP-EMPID, zyyTC_EMP-DEPID, zyyTC_EMP-CLASS, zyyTC_EMP-SEX, zyyTC_EMP-BIRTH, zyyTC_EMP-ADDRESS. ENDSELECT. IF SY-SUBRC <> 0. WRITE : / 'There is no record in the table.'. ELSE. WRITE : / 'Table has at least one record.'. ENDIF.

9. 練習E • 將abap-dictionary之TABLE複製到Internal Table(程式名稱zyy**_ex_e) • 宣告表格zyy**_EMP。 • 宣告一Work Area變數，結構如zyy**_EMP • 宣告一Internal Table變數，型態如zyy**_EMP • 利用SQL指令，將zyy**_EMP逐筆複製到Work Area，再將之新增入Internal Table • 印出Internal Table所有內容。

10. 練習E參考解答 REPORT zyyTC_EX_E . TABLES zyyTC_EMP. DATA wa LIKE zyyTC_EMP. DATA itab TYPE STANDARD TABLE OF zyyTC_EMP WITH HEADER LINE. SELECT * FROM zyyTC_EMP INTO CORRESPONDING FIELDS OF wa. APPEND wa TO itab. ENDSELECT. LOOP AT itab. WRITE: / itab. ENDLOOP.

11. 4. Subroutines • 第一行以FORM開始，最後一行以ENDFORM結束

12. 相同記憶體位址 CHANGING fv3 呼叫副程式 USING VALUE (fv1) CHANGING 不同位址，但回傳後更改其值 CHANGING VALUE (fv2) 參數傳遞方式

13. 練習F • 計算總和副程式 (程式名稱zyy**_ex_f) • 定義整數變數n，並設定n為6，請分別呼叫以下兩支副程式，再印出n值。 • 副程式1：利用call by value • 根據傳來的n值，印出n平方 • 副程式2：利用call by reference • 根據傳來的n值，印出n平方

14. 練習F參考解答 REPORT zyyTC_EX_F . DATA N TYPE I. N = 6. PERFORM SQUARE1 USING N. WRITE: / 'N=', N. ULINE. PERFORM SQUARE2 CHANGING N. WRITE: / 'N=', N. FORM SQUARE1 USING VALUE(X). X = X * X. WRITE: / 'Square1: N^2=', X. ENDFORM. FORM SQUARE2 CHANGING X. X = X * X. WRITE: / 'Square1: N^2=', X. ENDFORM.

15. 5. Event Block • 類似視窗系統之事件，無一定之執行順序，而由 runtime system 所決定 • 用法: • 第一行以keyword為起始，無結束keyword • 直到遇到下一個event block或FORM keyword才結束

16. Event Blocks for Reports

17. Event Blocks for Reports (Cont.) • The runtime environment creates the INITIALIZATION event and calls the event block. • If there is a selection screen defined in the program, control returns to the selection screen processor. • Control then passes to the reporting processor. It creates the START-OF-SELECTION event. • The logical database, if you are using one, calls further event blocks at this point. • The reporting processor creates the END-OF-SELECTION event. • If the program contains a list description, it displays the list defined in the AT LINE-SELECTION event.

18. Major Event Blocks 設定初值 Basic list要用到的 event，用來產生report 範例 PARAMETERS INPUTN TYPE I. START-OF-SELECTION. IF INPUTN = 1 . WRITE : 'HI!'. ENDIF.

19. Major Event Blocks (Cont.) • AT LINE-SELECTION • Detail list所用到的 event • 報表Drill-down(向下挖掘)之用 • 可利用 IF 來控制選擇層數：Basic list有參數值sy-lsind = 0，第一層sy-lsind = 1，最多可至20層 • 範例 REPORT …… ……………… AT LINE-SELECTION. IF sy-lsind = 1. SELECT * FROM spfli INTO CORRESPONDING FIELDS OF wa_flight WRITE :/ wa_flight-carrid, wa_flight-connid. ENDSELECT. IF sy-lsind = 2. ………………