PostgreSQL triggers for data change audits

audit_triggers.sql

DROP SCHEMA IF EXISTS edgar CASCADE;
CREATE SCHEMA edgar AUTHORIZATION spoton;

DROP TABLE IF EXISTS edgar.people;
CREATE TABLE edgar.people (id INTEGER PRIMARY KEY, name TEXT NOT NULL);

DROP TABLE IF EXISTS edgar.dumb_audits;
CREATE TABLE edgar.dumb_audits (
  op TEXT NOT NULL,
  stamp TIMESTAMP NOT NULL,
  tname TEXT NOT NULL,
  rid INTEGER NOT NULL
);

CREATE OR REPLACE FUNCTION edgar.paudits() RETURNS TRIGGER AS $paudits$
  BEGIN
    IF (TG_OP = 'INSERT') THEN
      INSERT INTO edgar.dumb_audits
      VALUES (
        'I',
        now(),
        TG_TABLE_NAME,
        (CASE WHEN TG_TABLE_NAME = 'people' THEN NEW.id ELSE 0 END)
      );
      RETURN NEW;
    ELSIF (TG_OP = 'UPDATE') THEN
      INSERT INTO edgar.dumb_audits
      VALUES (
        'U',
        now(),
        TG_TABLE_NAME,
        (CASE WHEN TG_TABLE_NAME = 'people' THEN NEW.id ELSE 0 END)
      );
      RETURN NEW;
    ELSIF (TG_OP = 'DELETE') THEN
      INSERT INTO edgar.dumb_audits
      SELECT  'D', now(), TG_TABLE_NAME,
        (CASE WHEN TG_TABLE_NAME = 'people' THEN OLD.id ELSE 0 END);
      -- VALUES (
      --   'D',
      --   now(),
      --   TG_TABLE_NAME,
      --   (CASE WHEN TG_TABLE_NAME = 'people' THEN NEW.id ELSE 0 END)
      -- );
      RETURN OLD;
    END IF;
  END;
$paudits$ LANGUAGE plpgsql;

DROP TRIGGER IF EXISTS dumb_audit ON edgar.people;
CREATE TRIGGER dumb_audit
AFTER INSERT OR UPDATE OR DELETE ON edgar.people
  FOR EACH ROW EXECUTE PROCEDURE edgar.paudits();

INSERT INTO edgar.people VALUES (1, 'Edgar Ramirez');
INSERT INTO edgar.people VALUES (2, 'Benito Juárez');
UPDATE edgar.people SET name = 'Edgar Ramirez Mondragon' WHERE id = 1;
DELETE FROM edgar.people WHERE id = 2;
UPDATE edgar.people SET name = 'Edgar Jaime Ramirez Mondragon' WHERE id = 1;

SELECT rid, MAX(stamp)
FROM edgar.dumb_audits
WHERE op = 'I' OR op = 'U'
GROUP BY rid;