Hi Dhanuka,
BI system allows only up to 60 length. STXT-20,MDTXT-40,LGTXT-60.
then you want increase the data type was 4000 for comment object.
create some more info objects as char 60 data type as CHAR.
map the transformation level source to target objects
write the field level routine for all info objects.
IO1: RESULT = SOURCE_FIELDS-<FIELD NAME>+0(60).
IO2: RESULT = SOURCE_FIELDS-<FIELD NAME>+60(120).
IO3: RESULT = SOURCE_FIELDS-<FIELD NAME>+120(180).
IO4: RESULT = SOURCE_FIELDS-<FIELD NAME>+180(240).
IO5: RESULT = SOURCE_FIELDS-<FIELD NAME>+240(300).
IO6: RESULT = SOURCE_FIELDS-<FIELD NAME>+300(360).
IO7: RESULT = SOURCE_FIELDS-<FIELD NAME>+360(420). -----------
IOX: RESULT = SOURCE_FIELDS-<FIELD NAME>+XXXX(XXXX).
Mean while please find the below document.
Long texts in SAP BW: Modeling
hope it will help.
Thanks,
Phani.