set default to existing column oracle code example

Example: oracle alter table add column default value

alter table DWSODS01.DWT00301_ORD_DTL_OMS add (
COMB_ORD_FLG NUMBER(5,0) default 0 not nulll); 

alter table DWSODS01.DWT00301_ORD_DTL_OMS add (
COMB_ORD_NO NUMBER(12,0) default 0 not null);