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
$$
DECLARE
BEGIN
    IF TG_OP = 'UPDATE' THEN
        NEW.created_at := OLD.created_at;
        NEW.created_by := OLD.created_by;
        NEW.updated_at := OLD.updated_at;
        NEW.version := OLD.version;
        IF row (NEW.*) IS DISTINCT FROM row (OLD.*) THEN
            NEW.updated_at := CURRENT_TIMESTAMP;
            NEW.version := OLD.version + 1;
            RETURN NEW;
        ELSE
            RETURN OLD;
        END IF;

    ELSIF TG_OP = 'INSERT' THEN
        NEW.created_at := CURRENT_TIMESTAMP;
        NEW.updated_at := CURRENT_TIMESTAMP;
        NEW.updated_by := NEW.created_by;
        NEW.version := 0;
        RETURN NEW;
    END IF;
END;
$$
;

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();

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