Postgres Function and Trigger to Update Audit Metadata Fields

update_audit_metadata_function.sql

CREATE OR REPLACE FUNCTION public.update_audit_metadata()
  RETURNS trigger
  LANGUAGE 'plpgsql'
AS
$function$
BEGIN
  NEW.created_at := OLD.created_at;
  NEW.created_by := OLD.created_by;
  NEW.version := OLD.version;
  IF row (NEW.*) IS DISTINCT FROM row (OLD.*) THEN
    NEW.updated_at := now();
    NEW.version := OLD.version + 1;
    RETURN NEW;
  ELSE
    RETURN OLD;
  END IF;
END;
$function$

update_audit_metadata_trigger.sql

CREATE OR REPLACE TRIGGER bu_{tablename}_update_audit_metadata
    BEFORE UPDATE
    ON "schema"."tablename"
    FOR EACH ROW
EXECUTE PROCEDURE update_audit_metadata();