Table audit system

Hello list,

I need to define an audit system that would be easyli include or exclude
certain tables, the process is a purchase order where many users changes
the info in diferent ways, the requerimient is to log the stamp and user
of the change on a table and additionaly log a snapshot of the the order
at the time it was change, that must include any child table too,
generally the order document includes the order header main table, the
order detail child table, the order costs child table and the order
comment history child table. So given the need to log a full snapshot
not only the change of a column I ask you for ideas or suggestion to get
this properly done in Postgresql.

Thanks in advance,

--
Sinceramente,
Josué Maldonado.

... "Toda violación de la verdad no es solamente una especie de suicidio
del embustero, sino una puñalada en la salud de la sociedad humana."
Ralph Waldo Emerson. Filósofo, ensayista, poeta y político EE.UU.