Is it possible to change column type to serial?

Question

PostgreSQL

There is a table with filled data:

CREATE TABLE "Виплата"
(
  old integer NOT NULL,
  "Код_договору" integer,
  "Дата" timestamp(0) without time zone,
  "Сума_виплат" text,
  "Оплата" boolean,
  "Код" integer,
  CONSTRAINT "Виплата_pkey" PRIMARY KEY (old)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE "Виплата"
  OWNER TO postgres;

Be sure to change the column type "Code" to serial! Ordinary

ALTER: ALTER TABLE "Виплата" ALTER COLUMN "Код" type serial;

I can't do it, because serial is not a type. ERROR: type "serial" does not exist !But it is very necessary to do this.
In what way it is possible to implement it?

Answer 1

SERIAL in PostreSQL is not a data type , but an alias for creating a SEQUENCE and DEFAULT VALUE for a column from it. Accordingly, you can manually do the described actions:

CREATE SEQUENCE tablename_colname_seq;
alter TABLE "Виплата" alter column "Код" type integer NOT NULL DEFAULT nextval('tablename_colname_seq');
ALTER SEQUENCE tablename_colname_seq OWNED BY "Виплата"."Код";

Answer 2

Only the following sequence of actions comes to mind: adding a new field with the serial type, changing the values ​​in it from Code, deleting Code, renaming the saerial field to Code.
Why are the field names in Russian? Eye hurts :)