Update timestamp when row is updated in PostgreSQL

Question

In MySQL, we can execute this where it updates the column changetimestamp every time the row is changed:

create table ab (   id int,    changetimestamp timestamp      NOT NULL      default CURRENT_TIMESTAMP      on update CURRENT_TIMESTAMP  ); 

Is there something similar to do the above in PostgreSQL?

Answer 1

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();