How to Read Table Dynamically in ABAP/4

About statement "READ TABLE", we can generate code for read key dynamic as below:

DATA: BEGIN OF itab OCCURS 0,
fld1(2),

fld2(2),

fld3(10),

fld4 TYPE i,

END OF itab,

wa_tab LIKE itab,

gv_key1(4) TYPE C VALUE ’FLD1’,

gv_key2(4) TYPE C VALUE ’FLD2’.

...

...

...

READ TABLE itab INTO wa_tab
WITH KEY (gv_key1) = ’AA’
(gv_key2) = ’BB’.