Sometime we need to update timestamp-column when row is changed. there are a lot of solution that you do. figure out about it...
one way to just do updating sql or other way to use trigger.
I am going to tell you about trigger is good sometime is not.
I got following post from stackoverflow, some people uploaded
In Mysql, do like the following thing.
create table ab ( id int, changeTimestamp timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP );
but In PostgreSQL is not worked. so there is other solution i got from stackoverflow. you can refer the following thing.
Create a function that updates the changetimestamp column of a table like so:
CREATE OR REPLACE FUNCTION update_changetimestamp_column() RETURNS TRIGGER AS $$ BEGIN NEW.changetimestamp = now(); RETURN NEW; END; $$ language 'plpgsql';
Create a trigger on the table that calls the update_changetimestamp_column() function whenever an update occurs like so:
CREATE TRIGGER update_ab_changetimestamp BEFORE UPDATE ON ab FOR EACH ROW EXECUTE PROCEDURE update_changetimestamp_column();
That's the solution i got. if you need more information, just refer the top of url. thanks for reading.