变量及对象声明
1.1 变量声明
Before:
DATA text TYPE string.
text = ....
After:
DATA(text) = ....
1.2 使用工作区
Before:
DATA wa like LINE OF itab.
LOOP AT itab INTO wa.
…
ENDLOOP.
After:
LOOP AT itab INTO DATA(wa).
…
ENDLOOP.
1.3 返回参数
Before:
DATA xml TYPE xstring.
CALL TRANSFORMATION … RESULT XML xml.
After:
CALL TRANSFORMATION … RESULT XML DATA(xml).
1.4 引用声明
Before:
DATA ixml TYPE REF TO if_ixml.
DATA stream_factory TYPE REF TO if_ixml_stream_factory.
DATA document TYPE REF TO if_ixml_document.
ixml = cl_ixml=>create( ).
stream_factory = ixml->create_stream_factory( ).
document = ixml->create_document( ).
After:
DATA(ixml) = cl_ixml=>create( ).
DATA(stream_factory) = ixml->create_stream_factory( ).
DATA(document) = ixml->create_document( ).
1.5 对象实例化
Before:
DATA lo_human TYPE REF TO class_human.
CREATE OBJECT lo_human EXPORTING NAME = ‘TONY’.
After:
lo_human = NEW class_human( name = ‘TONY’ ).
内表操作
2.1 READ TABLE
2.1.1 Read Table with key
Before:
READ TABLE flight_schedules INTO DATA(flight_schedule)
WITH KEY carrid = ‘AA’
connid = ‘0017’.
After:
DATA(flight_schedule) = flight_schedules[ carrid = ‘AA’ connid = ‘0017’ ].
2.1.2 Read Table index
Before:
READ TABLE itab INDEX idx
INTO wa.
After:
wa = itab[ idx ].
2.1.3 Read Table using key
Before:
READ TABLE itab INDEX idx
USING KEY key
INTO wa.
After:
wa = itab[ KEY key INDEX idx ].
2.1.4 Read Table index
Before:
DATA idx type sy-tabix.
READ TABLE …
TRANSPORTING NO FIELDS.
idx = sy-tabix.
After:
DATA(idx) = line_index( itab[ … ] ).
2.1 READ TABLE ASSIGNING
Before:
FIELD-SYMBOLS:
type …
READ TABLE itab
ASSIGNING
.
After:
READ TABLE itab
ASSIGNING FIELD-SYMBOL(
).
2.2 获得内表行数
Before:
DATA: lv_rows TYPE i.
LV_ROWS = LINES( ITAB)
After:
DATA(lv_rows) = LINES( itab ).
2.3 填充内表的值到目标内表中
Before:
DATA: gt_citys TYPE ty_citys,
gs_ship TYPE ty_ship,
gs_city TYPE ort01.
LOOP AT gt_ships INTO gs_ship.
gs_city = gs_ship-city.
APPEND gs_city TO gt_citys.ENDLOOP.
After:
DATA(gt_citys) = VALUE ty_citys( FOR ls_ship IN gt_ships ( ls_ship-city ) ).
Open SQL
3.1 取数到内表
Before:
DATA itab TYPE TABLE OF dbtab.
SELECT * FROM dbtab
INTO TABLE itab
WHERE fld1 = lv_fld1.
After:
SELECT * FROM dbta
INTO TABLE DATA(itab)
WHERE fld1 = @lv_fld1
3.2 宿主变量
在ABAP 7.40之前,OPEN SQL 中我们通常会添加一些变量,用来作为取数的限制条件,这种方式下,Open SQL parser将open SQL语句进行解析成与底层数据可相对应SQL时,可能会出现误差,为了能清晰的区分算符两端的东西到底是ABAP变量、还是数据库内容,从而发送相应的内容给数据库。为了完成这一任务,Open SQL中的ABAP变量因此成为了完全的宿主变量(host variables)。
宿主变量用”@ ”来标记。
3.3 宿主表达式
Before:
没有宿主变量之前,书写SQL时,可能会出现下面的错误。并且不容易察觉。
1)SELECT carrid connid fldate seatsocc seatsmax
FROM sflight INTO TABLE sflight_tab
WHERE seatsmax < sflight-seatsocc.
2)SELECT carrid, connid, fldate, seatsocc, seatsmax
FROM sflight
WHERE seatsmax < sflight~seatsocc
INTO TABLE sflight_tab.
第一种情况 sflight-seatsocc表示的是变量,而第二种sflight~seatsocc则表示的是数据库字段
他们的执行结果是不同的。
After:
3)SELECT carrid, connid, fldate, seatsocc, seatsmax
FROM sflight
WHERE seatsmax < @sflight-seatsocc
INTO TABLE @sflight_tab.
引入宿主变量之后,通过@符号,我们能准确区分@sflight-seatsocc
是宿主变量,也就是程序中的变量,执行结果不会出现误差。
其他语法
4.1 FILTER
语法定义:
FILTER type( itab [EXCEPT] [IN ftab] [USING KEY keyname]
WHERE c1 op f1 [AND c2 op f2 […]] ).
实例:
TYPES: BEGIN OF ty_filter,
cityfrom TYPE spfli–cityfrom,
cityto TYPE spfli–cityto,
f3 TYPE i,
END OF ty_filter,
ty_filter_tab TYPE HASHED TABLE OF ty_filter
WITH UNIQUE KEY cityfrom cityto.
DATA: lt_splfi TYPE STANDARD TABLE OF spfli.
SELECT * FROM spfli APPENDING TABLE lt_splfi.
DATA(lt_filter) = VALUE ty_filter_tab( f3 = 2
( cityfrom = ‘NEW YORK’ cityto = ‘SAN FRANCISCO’ )
( cityfrom = ‘FRANKFURT’ cityto = ‘NEW YORK’ ) ).DATA(lt_myrecs) = FILTER #( lt_splfi IN lt_filter
WHERE cityfrom = cityfrom
AND cityto = cityto ).
“Output filtered records
LOOP AT lt_myrecs ASSIGNING FIELD–SYMBOL(<ls_rec>).
WRITE: / <ls_rec>–carrid,8 <ls_rec>–cityfrom,30
<ls_rec>–cityto,45 <ls_rec>–deptime.
ENDLOOP.
4.2 REDUCE
语法定义:
… REDUCE type(
[let_exp]
INIT {x1 = rhs1}|{ = wrexpr1}|{x1| TYPE dtype1}
{x2 = rhs2}|{ = wrexpr2}|{x2| TYPE dtype2}
…
FOR for_exp1
FOR for_exp2
…
NEXT …
{x1 = rhs1}|{ = wrexpr1}
{x2 = rhs2}|{ = wrexpr2}
… ) …
实例:
DATA itab TYPE STANDARD TABLE OF i WITH EMPTY KEY.
itab = VALUE #( FOR j = 1 WHILE j <= 10 ( j ) ).DATA(sum) = REDUCE i( INIT x = 0 FOR wa IN itab NEXT x = x + wa ).
4.3 使用类转换字符串 conv
Before:
DATA text TYPE c LENGTH 255.
DATA helper TYPE string.
DATA xstr TYPE xstring.
helper = text.
xstr = cl_abap_codepage=>convert_to( source = helper ).
After:
DATA text TYPE c LENGTH 255.
DATA(xstr) = cl_abap_codepage=>convert_to( source = CONV string( text ) ).
OR
DATA(xstr) = cl_abap_codepage=>convert_to( source = CONV #( text ) ).