ABAP--两个提高ABAP代码效率的优化方法

一、利用内表缓冲减少数据库访问次数

REPORT zmmi003.

data: it_vbap type table of vbap,
wa_vbap type vbap,
it_makt type table of makt,
wa_makt type makt.
perform process.
perform process_using_cursor.
*&---------------------------------------------------------------------*
*& Form process
*&---------------------------------------------------------------------*
* text
*----------------------------------------------------------------------*
FORM process .
DATA: t1 TYPE i,
t2 TYPE i,
tmin TYPE i.
get run time field t1.
select * into wa_vbap
up to 10000 rows
from vbap .
select single * into wa_makt
from makt
where matnr = wa_vbap-matnr.
* write:/ wa_makt-MAKTX.
endselect.
get run time field t2.
tmin = t2 - t1.
write:/ '------------------------------------------------------------------'.
write:/ 'Time(ms):' ,tmin.
ENDFORM. " process
*&---------------------------------------------------------------------*
*& Form process_using_cursor
*&---------------------------------------------------------------------*
* text
*----------------------------------------------------------------------*
FORM process_using_cursor .
DATA: t1 TYPE i,
t2 TYPE i,
tmin TYPE i.
get run time field t1.
select * into wa_vbap
up to 10000 rows
from vbap .
read table it_makt into wa_makt with key matnr = wa_vbap-matnr binary search.
if sy-subrc = 0.
* write:/ wa_makt-MAKTX.
else.
select single * into wa_makt
from makt
where matnr = wa_vbap-matnr.
* write:/ wa_makt-MAKTX.
APPEND wa_makt to it_makt SORTED BY matnr.
endif.
endselect.
get run time field t2.
tmin = t2 - t1.
write:/ '------------------------------------------------------------------'.
write:/ 'Time(ms):' ,tmin.
ENDFORM. " process_using_cursor

Time(ms): 4.735.194

Time(ms): 3.411.177

二、利用一条read table来提高loop 访问速度

data: it_mara type table of mara,
wa_mara type mara,
it_makt type table of makt,
wa_makt type makt.
select *
up to 100 rows
from mara
into table it_mara.
select *
up to 100 rows
from makt
into table it_makt.
perform process.
perform process_using_cursor.
*&---------------------------------------------------------------------*
*& Form process
*&---------------------------------------------------------------------*
* text
*----------------------------------------------------------------------*
FORM process .
DATA: t1 TYPE i,
t2 TYPE i,
tmin TYPE i.
get run time field t1.
* sort it_mara by matnr.
sort it_makt by matnr.
loop at it_mara into wa_mara.
loop at it_makt into wa_makt where matnr = wa_mara-matnr.
endloop.
endloop.
get run time field t2.
tmin = t2 - t1.
write:/ 'Time(ms):' ,tmin.
ENDFORM. " process
*&---------------------------------------------------------------------*
*& Form process_using_cursor
*&---------------------------------------------------------------------*
* text
*----------------------------------------------------------------------*
FORM process_using_cursor .
DATA: t1 TYPE i,
t2 TYPE i,
tmin TYPE i,
tabix type sy-tabix.
get run time field t1.
* sort it_mara by matnr.
sort it_makt by matnr.
loop at it_mara into wa_mara.
read table it_makt transporting no fields with key matnr = wa_mara-matnr.
if sy-subrc = 0.
tabix = sy-tabix.
loop at it_makt into wa_makt from tabix.
if wa_makt-matnr <> wa_mara-matnr.
exit.
endif.
endloop.
endif.
endloop.
get run time field t2.
tmin = t2 - t1.
write:/ 'Time(ms):' ,tmin.
ENDFORM. " process_using_cursor