How to check in a trigger if the entire row remains the same after an update?
You can simply compare the old and the new records using is not distinct from which handles NULL values correctly (if all columns are defined as NOT NULL you can simply use = or &lt;&gt;)

if old is not distinct from new then 
   .... do something
end if;


The same can be done to check if at least one column changed:

if old is distinct from new then 
   .... do something
end if;