68 lines
2 KiB
Text
68 lines
2 KiB
Text
drop table tttest;
|
|
|
|
create table tttest (
|
|
price_id int4,
|
|
price_val int4,
|
|
price_on abstime,
|
|
price_off abstime
|
|
);
|
|
|
|
create trigger timetravel
|
|
before insert or delete or update on tttest
|
|
for each row
|
|
execute procedure
|
|
timetravel (price_on, price_off);
|
|
|
|
insert into tttest values (1, 1, null, null);
|
|
insert into tttest(price_id, price_val) values (2, 2);
|
|
insert into tttest(price_id, price_val,price_off) values (3, 3, 'infinity');
|
|
|
|
insert into tttest(price_id, price_val,price_off) values (3, 3,
|
|
abstime('now'::timestamp - '100 days'::interval));
|
|
insert into tttest(price_id, price_val,price_on) values (3, 3, 'infinity');
|
|
|
|
select * from tttest;
|
|
delete from tttest where price_id = 2;
|
|
select * from tttest;
|
|
-- what do we see ?
|
|
|
|
-- get current prices
|
|
select * from tttest where price_off = 'infinity';
|
|
|
|
-- change price for price_id == 3
|
|
update tttest set price_val = 30 where price_id = 3;
|
|
select * from tttest;
|
|
|
|
-- now we want to change price_id from 3 to 5 in ALL tuples
|
|
-- but this gets us not what we need
|
|
update tttest set price_id = 5 where price_id = 3;
|
|
select * from tttest;
|
|
|
|
-- restore data as before last update:
|
|
select set_timetravel('tttest', 0); -- turn TT OFF!
|
|
delete from tttest where price_id = 5;
|
|
update tttest set price_off = 'infinity' where price_val = 30;
|
|
select * from tttest;
|
|
|
|
-- and try change price_id now!
|
|
update tttest set price_id = 5 where price_id = 3;
|
|
select * from tttest;
|
|
-- isn't it what we need ?
|
|
|
|
select set_timetravel('tttest', 1); -- turn TT ON!
|
|
|
|
-- we want to correct some date
|
|
update tttest set price_on = 'Jan-01-1990 00:00:01' where price_id = 5 and
|
|
price_off <> 'infinity';
|
|
-- but this doesn't work
|
|
|
|
-- try in this way
|
|
select set_timetravel('tttest', 0); -- turn TT OFF!
|
|
update tttest set price_on = '01-Jan-1990 00:00:01' where price_id = 5 and
|
|
price_off <> 'infinity';
|
|
select * from tttest;
|
|
-- isn't it what we need ?
|
|
|
|
-- get price for price_id == 5 as it was '10-Jan-1990'
|
|
select * from tttest where price_id = 5 and
|
|
price_on <= '10-Jan-1990' and price_off > '10-Jan-1990';
|