create table userinfo
( id int not null,
  full_name varchar(1024),
  user_name varchar(128),
  user_host varchar(128),
  user_ip4 varchar(128),
  user_ip6 varchar(128)
)

insert into userinfo(full_name)

'domain\petya#petin_computer#192.168.1.2#::1'

CREATE TABLE userinfo (
  id        serial  not null,
  full_name text    not null,
  user_name text,
  user_host text,
  user_ip4  text,
  user_ip6  text
);
CREATE OR REPLACE FUNCTION tf_users() RETURNS trigger AS $t_users$
BEGIN
  NEW.user_name=coalesce(NEW.user_name,split_part(NEW.full_name,'#',1));
  NEW.user_host=coalesce(NEW.user_host,split_part(NEW.full_name,'#',2));
  NEW.user_ip4=coalesce(NEW.user_ip4,split_part(NEW.full_name,'#',3));
  NEW.user_ip6=coalesce(NEW.user_ip6,split_part(NEW.full_name,'#',4));
  RETURN NEW;
END; $t_users$ LANGUAGE plpgsql;
CREATE TRIGGER b_userinfo BEFORE INSERT OR UPDATE ON userinfo FOR EACH ROW EXECUTE PROCEDURE tf_users();

INSERT INTO userinfo(full_name) VALUES ('domain\petya#petin_computer#192.168.1.2#::1');
SELECT * FROM userinfo;