create table spr_tem
(
  id bigint NOT NULL DEFAULT nextval(('id_spr_tem_seq'::text)::regclass),
  code bigint,
  name text,
  date_begin timestamp default now(),
  date_end timestamp default '2999-12-31',  
  id_parent bigint, 
  CONSTRAINT pk_spr_tem PRIMARY KEY (id)
);

CREATE OR REPLACE FUNCTION tg_spr_tem_before_ins()
  RETURNS trigger AS
$BODY$ --обновляем код
begin 
  raise notice 'ins';
  if new.code is null then new.code = new.id;end if;
  return new;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_ins ON spr_tem;
CREATE TRIGGER tg_spr_tem_ins BEFORE INSERT ON spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_ins();  

CREATE OR REPLACE FUNCTION tg_spr_tem_before_upd()
  RETURNS trigger AS
$BODY$
begin --помечаем как удаленую
  raise notice 'upd';
  if new.code = old.code then old.date_end = new.date_begin;end if;
  return new;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_upd ON spr_tem;
CREATE TRIGGER tg_spr_tem_upd INSTEAD OF BEFORE spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_upd();

CREATE OR REPLACE FUNCTION tg_spr_tem_before_del()
  RETURNS trigger AS
$BODY$
begin --помечаем как удаленую
  raise notice 'del';
  old.date_end = now();
  return old;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_del ON spr_tem;
CREATE TRIGGER tg_spr_tem_del BEFORE DELETE ON spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_del(); 

CREATE OR REPLACE FUNCTION tg_spr_tem_before_upd()
  RETURNS trigger AS
$BODY$
begin --помечаем как удаленую
  raise notice 'upd';
  update spr_tem set date_end = new.date_begin where spr_tem.id = old.id;
  insert into spr_tem (code,name) values (new.code,new.name);
  old = null;
  new = null;
  return new;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_upd ON spr_tem;
CREATE TRIGGER tg_spr_tem_upd BEFORE UPDATE OF name ON spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_upd();  

CREATE OR REPLACE FUNCTION tg_spr_tem_before_del()
  RETURNS trigger AS
$BODY$
begin --помечаем как удаленую
  raise notice 'del';
  update spr_tem set date_end = now() where spr_tem.id = old.id;
  return null;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_del ON spr_tem;
CREATE TRIGGER tg_spr_tem_del BEFORE DELETE ON spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_del(); 

CREATE OR REPLACE FUNCTION tg_spr_tem_before_upd()
  RETURNS trigger AS
$BODY$
begin --помечаем как удаленую
  raise notice 'upd';
  --update spr_tem set date_end = now()/*new.date_begin*/ where spr_tem.id = old.id;
  --insert into spr_tem (code,name,date_begin) values (new.code,new.name,now());
  update spr_tem set date_end = new.date_begin where spr_tem.id = old.id;
  insert into spr_tem (code,name,date_begin) values (new.code,new.name,new.date_begin);  
  return null;
end;
$BODY$ LANGUAGE plpgsql VOLATILE COST 100;
DROP TRIGGER if exists tg_spr_tem_upd ON spr_tem;
CREATE TRIGGER tg_spr_tem_upd BEFORE UPDATE OF name ON spr_tem FOR EACH ROW EXECUTE PROCEDURE tg_spr_tem_before_upd();  

insert into spr_tem (name) values ('D');
update spr_tem set name = 'F' where name = 'E'