Hi, all

I tried to modify a column which would have sysdate as the default value, it worked as I enter:

alter table xxx
modify(created default sysdate);

But when I tried to modify a column so that it would accept the current login user as a default value, it didn't work.
This column has a datatype and size varchar2(16). I entered:

alter table xxx
modify(createdby default USER);

I'm getting an error:
ORA-01401 Inserted value too large for column.

So what's the right way to do it?