ABAP_to_the_Future

Recent Code Inspector Enhancements 4.3
DATA: lt_monsters TYPE STANDARD TABLE OF ztvc_monsters,
lt_selections TYPE RANGE OF zde_monster_number.
IF lt_selections[] IS NOT INITIAL.
SELECT *
FROM ztvc_monsters
INTO CORRESPONDING FIELDS OF TABLE lt_monsters
FOR ALL ENTRIES IN lt_selections
WHERE monster_number = lt_selections-low.
ENDIF.
Listing 4.3 Check for Empty Tables
If you rerun the Code Inspector, then you’ll find that the error message has vanished
like a phantom into the night.
4.3.2 SELECT * Analysis (14/9/2)
SELECT * analysis is a tool that identifies where you have used SELECT * in your
code so that you can then make sure th at you are only using it when absolutely
necessary. The reason you want to be careful with SELECT * is that it brings back
every single column from the database table being accessed—and this breaks the
golden rule of minimizing the amount of data being transferred from the database
to the application server.
In the example, a SELECT * has just been performed on the monsters table to bring
back every single column. Now, write some code as shown in Listing 4.4 to output
the desired result to the user.
LOOP AT lt_monsters INTO ls_monsters.
WRITE:/ ls_monsters-monster_number,
ls_monsters-hat_size.
ENDLOOP.
Listing 4.4 Ouputting the Result
Even though you’re only interested in two columns of the table, it turns out that
you’ve retrieved every single column from the database. This is naughty, because
it puts undue strain on the system. You should be ashamed of yourself.
Fortunately, you can use the Code Inspector default variant to fix this. Figure 4.18
shows the Search Problematic SELECT * Statements option; all you have to do
is make sure this option is checked in your system.
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