Sounds strange. I'd be curious at what values the a similar trigger would
show if you captured :old and :new.

Henry

-----Original Message-----
Sent: Thursday, May 03, 2001 12:35 PM
To: Multiple recipients of list ORACLE-L
R.I.


A developer has an "after update on <table_name> for each row ... " trigger
which sends mail via the UTL_SMTP package.  If the triggering  statement is
something like,  "update saltab set dba_salary = dba_salary * 1000", and the
resultant value is too large.  The mail is not sent.  However, if the
statement  is something like, "update saltab set foreign_key_column =
'QWERTY' where
foreign_key column = 'ASDFGH'", and an R.I. constraint violation occurs
because there is no parent key, "ASDFGH",  the mail is sent anyway. 

I had thought that R.I. checking was done in the following manner for such a
trigger:

1. execute triggering event;  2. check for R.I. violations resulting from
step 1; 3. execute trigger logic;  4. check for R.I. violations caused by
the trigger; 5.  Repeat for each row.
    
(In this case the trigger just sends mail so step 4 can be removed).


If this sequence of  events is correct why is the mail sent?  Is the R.I.
violation not placed on the error stack immediately? That seems unlikely.
Is the error stack not read until after the mail is sent?  It was read for a
non-R.I. violation.  Is Oracle programmed to defer  reporting R.I.
violations on the error stack until after he trigger logic is processed?

I could be wrong in my understanding of the trigger logic;  step 2 is
performed after step 3?

How does one stop the mail from being sent when an R.I. violation occurs.
One way would be  to do the RI checking in trigger  via a cursor which
queries the parent table, and then raises an exception  if no parent key is
found.  Is there another way?

Ian MacGregor
Stanford Linear Accelerator Center
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