Alex,

A> Addition of non-required clause except

A> if (old is distinct from new except field5, field8, field123)
A> then do_something;

A> can be even more useful (i.e. compare all fields except listed). Though this
A> looks like really new feature, not depending from ROW datatype.

it still relies on the row datatype if you also have a type
constructor and a difference operator. Something like

if (old - {field5, field8, field123} is distinct from
new - {field5, field8, field123}) then do_something;

assuming {} is the constructor and - the difference operator.

Ciao
--
Nando Dessena