How to add column in existing oracle table with not null constraint

Question

I am using below statement but i got error.
ALTER TABLE XXXtable
ADD xxx_name varchar2(50) not null;

error message:
ORA-01758: table must be empty to add mandatory (NOT NULL) column

Answer 1

ALTER TABLE XXXtable
ADD xxx_name varchar2(50) not null;

add a default value clause along with your alter table.
with that, although the new column is not null, and already has a value assigned to it through the default clause.

Answer 2

Hi Arun,

below is the syntax for query

ALTER TABLE emp
ADD supplier_name varchar2(50) default ('A') not null;