<<<<<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.>>>>
Actually, most windows-based database applications (e.g., MS Access; Paradox; even FileMaker) do allow for on-the-fly changes to the structure. Yes, for some of the changes, they do require that exclusive access be granted to the developer at the time of the change. They do not, however, remove the data from the database. Since the data is stored in separate "tables," which are completely separate from the queries, reports, forms, etc., removing the data is not necessary. Jerome R. Kinderman Lodi, California -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Hancock Sent: Sunday, April 15, 2007 8:09 PM To: Dataperfect Users Discussion Group Subject: Re: [Dataperf] Modifying structure file 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 * >> -------------------------------------------- >> _______________________________________________ >> Dataperf mailing list >> [email protected] >> http://lists.dataperfect.nl/mailman/listinfo/dataperf >> >> > _______________________________________________ > Dataperf mailing list > [email protected] > http://lists.dataperfect.nl/mailman/listinfo/dataperf > _______________________________________________ Dataperf mailing list [email protected] http://lists.dataperfect.nl/mailman/listinfo/dataperf _______________________________________________ Dataperf mailing list [email protected] http://lists.dataperfect.nl/mailman/listinfo/dataperf
