Re: [firebird-support] compaing NULL values like NEW,COLUMN and OLD.COLUMN in triggers

2012-11-26 Thread Helen Borrie 
At 03:16 p.m. 27/11/2012, Robert Gilland wrote:
>We need to do a lot of checking in update triggers to check for value changes.
>
>ie if( OLD.FIELD1 <> NEW.FIELD1 )OR( OLD.FIELD2 <> NEW.FIELD2 )THEN
>  DO SOMETHING;
>
>However if either value is NULL then the response will be NULL.
>
>Is there an easy way to compare values, taking into account these values may 
>be NULL?

 From v.2 onwards you can use the IS [NOT] DISTINCT FROM predicate.  (Look it 
up in the LangUpdate doc.) In 1.0 and 1.5 you're stuck with the multiple 
predicates.

./hb

[firebird-support] compaing NULL values like NEW,COLUMN and OLD.COLUMN in triggers

2012-11-26 Thread sir_wally_lewis 
We need to do a lot of checking in update triggers to check for value changes.

ie if( OLD.FIELD1 <> NEW.FIELD1 )OR( OLD.FIELD2 <> NEW.FIELD2 )THEN
  DO SOMETHING;

However if either value is NULL then the response will be NULL.

Is there an easy way to compare values, taking into account these values may be 
NULL?

Kind Regards,

Robert.