[Kexi] Re: Calculated fields in kexi

Jaroslaw Staniek staniek at kde.org
Wed Dec 8 09:19:21 CET 2010


On 7 December 2010 13:03, Neil Winchurst <neil at pamneil.com> wrote:
> On Mon, 6 Dec 2010 22:30:18 +0100
> Jaroslaw Staniek <staniek at kde.org> wrote:
>
>> On 6 December 2010 15:57, Neil Winchurst <neil at pamneil.com> wrote:
>> > I have searched but not found anything. Is it possible to include
>> > calculated fields on a form? That is, fields which give the result of a
>> > calculation on the form but which are not stored in any table.
>>
>> Not at the moment. Feel free to file a wish at bugs.kde.org, so we
>> have a starting point.
>> Thanks!
>>
> Thanks for the reply. My last 12 working years were spent writing
> databases for small companies. I used Borland Paradox, similar to
> Access but, IMHO, far superior. I have lost count of how many databases
> I actually wrote, but I do remember clearly that only one had no need
> for a calculated field.
>
> In my experience the facility to create a calculated field in a form is
> fundamental to any database and should be near the top of the list of
> what should be included from the very beginning of creating a new
> database program.
>
> I will not spend time going into details of how it worked in Paradox.
> Just let me say that the calculation was set up in the form and did not
> involve a query or a spreadsheet. The result of the calculation was not
> stored anywhere. If you were viewing any records that included
> calculated fields then those calculations were performed on the fly as
> you went along.

> When I moved from Windows to Linux I found plenty of choices for word
> processors, spreadsheets, text editors etc. The one big gaping hole was
> the lack of any monolithic database program like Access or Paradox.
> That was 12 years ago, and I am still waiting.
>
> I am not sure about adding it as a bug in kde.org. It is not really a
> bug, it is a missing, essential facility. It was available and easy to
> set up in Paradox as long ago as 1992. For me it should have been
> included in Kexi right from the start. By the way,  OO Base does not
> have it either.

Hi Neil,
Thanks for your explanation and espacially sharing your desktop
database experience.
We would like to have such specialists with such history in this community!
I am also ex-MS Access user after all.

First, regarding bugs.kde.org - it accepts both bugs and wishes. At
the beginning of reporting it looks like you're reporting bug, but
later you could set the type of bug as a *wish*. This is the right way
of organizing our work, so I enourage to go this way.
Also if someone will report similar wish in the future, the new report
will be redirected as a duplicate to your wish.

Regarding the merits, the calculated fields could be supported  "out
of the box" of course. There are questions though:

If the form is based on query like "SELECT width, height, width*height
AS area FROM rectangles", then area column is calculated based on the
database engine. Newer apps like the newer MS Access allow to edit
fields in such forms even if the query itself is not editable as a
result of computation. I am aware of this very feature and has marked
in as TODO maybe 3 years ago or so.
If the form is based on "SELECT width, height FROM rectangles" and
computation of "area" is entered directly in a text field e.g. as
"=width*height" like in spreadsheets, then there's question of what
language (of scripts) to accept in the fields.
I am wondering allowing to select script type here (as in the script
object) would introduce chaos, because some users would use
javascript, some python, and some ruby expressions. I tend to think
about javascript/ECMAscript. With optional ability to call functions
defined in other languages through a bridge like KROSS.

>
> If you really think that I ought to put it on a wish list I will do so.

Yes I think so, thanks!

-- 
regards / pozdrawiam, Jaroslaw Staniek
 http://www.linkedin.com/in/jstaniek
 Kexi & Calligra (kexi-project.org, identi.ca/kexi, calligra-suite.org)
 KDE Software Development Platform on MS Windows (windows.kde.org)


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