April 16, 2007
Thanks Brian.
I was all set to miss the problem with auto increment fields. I shall
have to explore the alternative.
Don Codling
WP 12.0.0.602
DP 2.6x
Windows XP home, SP2
512 MBytes RAM
Brian Hancock wrote:
Hi,
The STR file can be modified and program updates distributed via a
portable "STR" within certain boundaries.
You cannot make a change to the STR which would change the layout of
the data files, ie the tables, so anything which adds, removes or
changes the Field Format on a panel, should not be done using the
portable STR. If you need to change these then you need to export the
data out when the changes is made and reimport after the change.
If you use :I incrementing number fields then updating an STR will be
a problem, as the STR file holds the value for the next record. If you
want your application to have a "portable" STR then you need to
replace all the :I field, with a technique described in Ralph Alvy'
book about using Recursive Panel Links for producing an incrementing
number... (The concept is simple you link a panel back to itself, and
by using a reversed index, when traversing the link you arrive at the
highest used incrementing number, you can add back your increment
using a formula through that link to increment the counter for the
newly created record). As an aside, using the recursive link for
numbering give a lot more flexibility, as you can choose the increment
or decrement value, or you can create complex incrementing number
patterns which can include alpha characters. One which I use alot is
an incrementing number with a generated check digit, so I might have a
sequece 0016, 0021, 0037,0049 where first 3 digits are the
incrementing number and the the final digit is a check digit
On the other hand you can use a "portable" STR to change field
formulae, link definitions, reports, colours, etc. If you change an
index, then you need to "bed" the new STR in by starting it with an
Index all (the easiest way to do that, is as soon as you have updated
the STR, start the updated application with the /IND startup switch.
For the web application work I am now doing with DP, most of the
application logic is in reports, and changing reports with a portable
STR is a piece of cake, providing you do not have :I incrementing
number fields.
I saw a complaint that DP forces you to empty data from the database
before you can make a change to the data structure, with the
implication that other products do not work that way. I think that
most products do empty the data first, it is just that the application
interfaces usually do that step for you without you knowing, by
creating a copy of the new structure and then copying the old records
back into the new one, then deleting the old and renaming the new.
There are very few database management systems which permit a totally
on-the-fly change to the data structures, and I think they all need
exclusive access by the definer for that time that the conversion is
taking place.
Regards
Brian
----- Original Message ----- From: "Don Codling"
<[EMAIL PROTECTED]>
To: "Dataperfect Users Discussion Group" <[email protected]>
Sent: Monday, April 16, 2007 11:13 AM
Subject: Re: [Dataperf] Modifying structure file
April 15, 2007
Thank you all. I see I can't change indexes, but the other things I'm
interested in can be done without a problem. I appreciate the help.
Don Codling
WP 12.0.0.602
DP 2.6x
Windows XP home, SP2
512 MBytes RAM
Bill Richardson wrote:
** Reply to note from Don Codling <[EMAIL PROTECTED]> Sun, 15
Apr 2007 20:53:58 -0300
| Can I make those kinds of changes in a client's database by giving
the
| client a modified Structure (.str) file to replace the existing one?
| That is, can I make the changes on a copy of the database on my
| computer, & simply replace that one file in the client's database? Or
| is it necessary to replace all of the client's files even for such
| changes? | | If I can just change the structure file, I can add
reports, change
| colours, etc, for a client, without interrupting his use of his
| database & its data.
Check out Mastering DataPerfect, pages 418 and following. It's not a
simple answer.
Bill
--------------------------------------------
* Wm. W. Richardson *
* Phone: 903/893-0506 *
* FAX: 903/893-7890 *
* Running at Warp speed under OS/2 *
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