Re: get all columns as a list

I am the OP. I was implementing what my customer asked for. But you
make a good point that they might want the latest data not the oldest.
I will suggest that to them. Thanks.

On Wed, May 25, 2016 at 9:29 AM, Derek <gamesbook@gmail.com> wrote:
> We are both speaking as non-users of the OP's system. ;)
>
> I agree that there are some use cases for keeping the first measurement IF
> the actual date of measurement makes no difference at all. We have an app
> like that, where we process real-time data and use a filter that only lets a
> record through if there has been a "change since previous". On the other
> hand, changing the date means that the user has some reassurance that status
> changes have been, and are, continuing to be made. I think we saying the
> same thing though: in general, in the absence of other constraints, try to
> retain as much data as possible and archive it in preference to simply
> tossing it.
>
> On Wednesday, 25 May 2016 00:52:01 UTC+2, James Schneider wrote:
>>
>>
>> On May 24, 2016 9:11 AM, "Derek" <game...@gmail.com> wrote:
>> >
>> > Interesting. In all the cases I can think of, I would almost always want
>> > to keep the most recent check (not the oldest)... that tells me how recently
>> > the status of X was checked. A more pedantic administrator might also want
>> > all those times stored, so a history can be created.
>> >
>>
>> Not necessarily. You would want record of the initial change, not a record
>> of the last time that value was seen. The assumption would be that the value
>> remained constant until the next change event. What happens when the sensor
>> goes offline and online, and then continues to report the same value on
>> initialization? You wouldn't see anything until the sensor reported a
>> changed value, which could be seconds, or years. That also means you've lost
>> a data point that probably should have been captured.
>>
>> In doing so, you also potentially save a ton of write operations, since
>> keeping the latest check would require extra logic to delete the old entry
>> and create the new entry, or update the existing entry in place.
>>
>> The use case for the data would be the driver for what data needs to be
>> retained. And also the use cases that haven't been thought of.
>>
>> I personally would prefer to keep all of the data points, and summarize
>> the data in a report using logic similar to the OP's storage strategy.
>> People tend to find interesting ways to use data, and you always end up with
>> egg on your face if you are summarizing/tossing the data on input rather
>> than filtering/analyzing output.
>>
>> Obviously this is all barring other technical restrictions that may
>> enforce a reduced data set.
>>
>> -James

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