Alter data type of a column to serial

Question

In pgsql, is there a way to have a table of several values, and choose one of them (say, other_id), find out what its highest value is and make every new entry that is put i

Answer 1

Look into postgresql documentation of datatype serial. Serial is only short hand.

CREATE TABLE tablename (
    colname SERIAL
);

is equivalent to specifying:

CREATE SEQUENCE tablename_colname_seq;
CREATE TABLE tablename (
    colname integer NOT NULL DEFAULT nextval('tablename_colname_seq')
);
ALTER SEQUENCE tablename_colname_seq OWNED BY tablename.colname;