Carol Walter <walterc(at)indiana(dot)edu> writes:
> Can I designate a column not
> previously defined as serial to serial.
"serial" is not really a type. It's just a convenience macro for
creating a sequence and setting the column's default expression.
So what you do is perform those steps manually. See
http://www.postgresql.org/docs/8.2/static/datatype-numeric.html#DATATYPE-SERIAL
regards, tom lane