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Re: Triggers, duh! :(

From: <n.a.ekern_at_usit.uio.no>
Date: 2000/06/14
Message-ID: <8i8vkv$ki6$1@readme.uio.no>#1/1

Tjenare!

Deal with Null-values using 'Is Null' and 'Is Not Null'. Don't mess it up with zero-strings.

To see if a date-column that does not have a Not Null-constraint has changed, check it like this:

If :new.date_signed <> :old.date_signed or
   :new.date_signed Is Null And :old.date_signed Is Not Null Or
   :new.date_signed Is Not Null And :old.date_signed Is Null Then

-- The column has changed

This is messy so you might want to create a utility-package with a function Date_Has_Changed that takes two dates as parameters and return s
True Or False.
Then in your trigger it will be:
If my_utilities.Date_Has_Changed(:new.date_signed, :old.date_sign ed) Then
-- The column has changed

Using the built-in function Updating is also an alternative, personally I don't use it because it doesn't check if the column values really has changed:
If Updating ("DATE_SIGNED") Then
-- The column is being updated but the value hasn't necessarilly changed

You are experiencing different behaviour in developing and testing because

Null-values occur differently in their data.

Helsningar,
Nj l Received on Wed Jun 14 2000 - 00:00:00 CDT

Original text of this message

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