nested select

Hi friends,

SELECT objectclas objectid changenr udate utime username FROM cdhdr

INTO (cdhdr-objectclas, cdhdr-objectid, cdhdr-changenr,

cdhdr-udate, cdhdr-utime, cdhdr-username)

WHERE objectclas = 'CLASSIFY'

AND objectid = x_objectid.

• ophalen nieuwe nieuwe waarde karakteristiek

SELECT tabkey value_new FROM cdpos

INTO (cdpos-tabkey, cdpos-value_new)

WHERE objectclas = cdhdr-objectclas

AND objectid = cdhdr-objectid

AND changenr = cdhdr-changenr

AND fname = 'ATWRT'.

• karakteristiek ophalen

*Begin of modification TCS196699 - BV898.

• SELECT SINGLE atnam FROM cabn INTO cabn-atnam

• WHERE atinn = cdpos-tabkey+20(8).

SELECT atnam FROM cabn INTO cabn-atnam

UP TO 1 ROWS

WHERE atinn = cdpos-tabkey+20(8).

ENDSELECT.

*End of modification TCS196699 - BV898.

IF sy-subrc <> 0.

CLEAR cabn.

ENDIF.

zbtch_class_char-matnr = p_matnr.

zbtch_class_char-werks = p_werks.

zbtch_class_char-charg = p_charg.

zbtch_class_char-atnam = cabn-atnam.

zbtch_class_char-changenr = cdhdr-changenr.

zbtch_class_char-udate = cdhdr-udate.

zbtch_class_char-utime = cdhdr-utime.

zbtch_class_char-username = cdhdr-username.

zbtch_class_char-value_new = cdpos-value_new.

MODIFY zbtch_class_char.

ENDSELECT.

ENDSELECT.

i want to improve the performane to the above code . How i can change the inside select query for better performance.Please help me.

Thanks for all.