[firebird-support] Update query and trigger

[Dr. Fabrizio Villanova]

hi all,

for example:


mytable
(
....
field_A varchar(x),
field_B integer default 0,
....
)


query:
update mytable set field_a=XXX where yyyyy;


mytrigger: before update
if(new.field_b>0) then
     dosomething;
else
     dosomethingelse;


the trigger must operate only when i update field_b not when i'm updating 
field_A.


Calling the first query new.field_b is always '0' and 'dosomethingelse' is 
executed; checking for "field_b is not null" is useless, it's '0'.
There is a way to recognize that the query is not altering field_b?


thank you.
Fabrizio