Subject Re: [firebird-support] Match two fields in same table using a trigger
Author Martijn Tonies
> Dne 11.3.2011 8:51, thedevguy napsal(a):
>> Is there a way to sync two columns in the same table using a trigger.
>> For example I have field1 and field2. On an insert or an update I would
>> like field2 = field1 if they are different.
>>


What's wrong with ALWAYS setting field2 = field1? If they're different, you
want them to be the same. Which means that if they're the same, you can copy
its value anyway.

With regards,

Martijn Tonies
Upscene Productions
http://www.upscene.com

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>> I tried something like the following but it doesn't work.
>>
>> TRIGGER:
>> if (new.field1<> old.field2) then
>> new.field2 = new.field1;
>>
>> Any help would be greatly appreciated.
>
> This kind of triggers works fine for me. I am pretty sure your
> particular implementation has some bugs, e.g. one of the fields contains
> a NULL value and the usual "comparison of anything to null is almost
> always false" GOTCHA kicks in.
>
> Pepak
>
>
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