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Re: time stamp specific to columns




A trigger is far simpler than remodelling your data and adding extra
queries.  They are nothing to be afraid of.

On Thu, Apr 9, 2015 at 10:46 AM, <hsv@xxxxxxxx> wrote:

> On 2015/04/08 11:42, Andrew Wallace wrote:
>
>> I think you'd have to do that with a trigger.
>>
>
> Yes, one can do that with a trigger, but it is a real pain. MySQL now
> allows
>         (new.a,new.b,new.c,new.d) <> (old.a,old.b,old.c,old.d)
> but one needs to beware of NULL. Maybe it is better to split off the
> timestampy part to another table, and join them when needed.
>
>
>  On 4/8/15 6:36 AM, Martin Mueller wrote:
>>
>>> I understand how a timestamp column automatically changes when there is a
>>> change in a data row. Is it possible to limit the update to changes in
>>> particular columns? I have a table where I care about changes in any of
>>> four different columns, but I don¹t care about changes in other
>>> columns or
>>> added columns.
>>>
>>> Is there a command that says ³update the time stamp if and only if there
>>> is a change in columns a, b,c, or d"
>>>
>>
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-- 
 - michael dykman
 - mdykman@xxxxxxxxx

 May the Source be with you.