PostgreSQL - Add primary key to an existing Table

postgresql_add_primary_key.sql

ALTER TABLE "public"."foo" ADD COLUMN "id" INTEGER;
CREATE SEQUENCE "public"."foo_id_seq";
UPDATE foo SET id = nextval('"public"."foo_id_seq"');
ALTER TABLE "public"."foo" ALTER COLUMN "id" SET DEFAULT nextval('"public"."foo_id_seq"');
ALTER TABLE "public"."foo" ALTER COLUMN "id" SET NOT NULL;
ALTER TABLE "public"."foo" ADD UNIQUE ("id");
ALTER TABLE "public"."foo" DROP CONSTRAINT "foo_id_key" RESTRICT;
ALTER TABLE "public"."foo" ADD PRIMARY KEY ("id");