Calculated fields in a database

manchicken manchicken at
Tue Jun 26 15:51:57 UTC 2007

On Tuesday 26 June 2007 08:41:24 Neil Winchurst wrote:
> I am learning knoda and hk-classes as a good way of setting up a
> databases on Linux. I have used Linux for six years now and I have been
> involved with databases for over 15 years. This knoda/mysql setup is
> the best I have found so far in Linux.
> I don't know about other people, but I find the help files rather
> difficult to follow sometimes. For example there is no page explaining
> how to set up a sub-form. I am still playing with that.
> Calculated fields. Let me give an example of what I mean. You have a
> list of people including date of birth. You need to have their age
> showing on the form. Obviously this will change with time. So you need
> a calculated field which takes the current date and subtracts the date
> of birth to calculate the age. Since this is a calculated field it will
> always be up to date and accurate.
> The important thing about this 'age' field is that **it is not part of
> any table. It appears on the form only.** There are other examples such
> as a sales form which has a field to calculate the cost for each item
> (price times quantity), and another field to show the total charge for
> all the items. Again, these two fields will not appear in any table,
> only on the form.
> Is there any way in knoda/hk-classes to do this sort of thing? It is a
> facility which I used again and again when I was writing databases in
> Windows (using Borland Paradox).
> Thanks for any help and/or information
> Neil Winchurst

You could always just stick it into your query.  I don't know how to do this 
in MySQL, butyou could just turn the two dates to epoch, subtract today from 
the birthdate, and then divide it by (60*60*24*365.25) to get the years.

~ manchicken <><
(A)bort, (R)etry, (I)nfluence with large hammer.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

Please avoid sending me Word or PowerPoint attachments.

More information about the kubuntu-users mailing list