table updation

hi all,

i want to modify a selected record of a database table

please tell me how i can do the same

i have done following

data: idx type sy-tabix.

data: itab type standard table of t508a." with header line.

data: wa_tab type t508a.

data: itab2 type standard table of t508a with header line.

select * from t508a into table itab

where zeity = '1'

and mofid = '11'.

• move itab to wa_tab.

idx = sy-tabix.

loop at wa_tab.

wa_tab-ENDDA = '99981231'.

MODIFY ITAB from wa_tab INDEX IDX

TRANSPORTING ENDDA.

endloop.

modify t508a from itab.

where t508a is a data base table like mara vbak and etc.

thanks in advance

pionts ll be surely awarded

anuj