New HDB files overwriting old Jfile DB's

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New HDB files overwriting old Jfile DB's

Postby pjk » Fri Mar 26, 2010 5:12 pm

I've long owned copies of both Jfile and HanDBase for PalmOS, although I've not really used HanDBase much. (Was my initial plan to migrate to HDB because of the richer functionality and the fact that JFile was no longer being supported.)

One of the factors in my recent decision to move to a Blackberry was the fact that HanDbase has a BB version. I figured I could migrate the Jfile databases to HDB, then migrate the HDB databases to the BB.

Since HDB does not import Jfile databases directly, I found an open-source program called DBconvert that reputes to do conversion between the two, and seems to work fine for that basic function. (although it just migrates the record data and none of the database attributes - which makes it little better than exporting/importing CSV I suppose, since I have to re-design popup lists, field restrictions and so on)

The problem seems to have something to do with HDB's HotSync conduit. Whenever I use DBconvert to convert a Jfile database to HDB format, as soon as I Hotsync the new files to my Treo 755p, it ERASES the Jfile databases on the Treo that these new databases were based upon.

At first I thought - OK, these programs are being dumb about it like MS WIndows, they see a ".PDB" file with the same name and don't realize it belongs to the other app, so they overwrite it.

So I re-did the conversion, specified a different destination filename for the new HDB files, Hotsynced again: SAME problem.

Then I tried manually installing the newly-renamed HDB files: SAME problem.

I think something in the HDB conduit is doing this. Can you help me please?
pjk
 
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Re: New HDB files overwriting old Jfile DB's

Postby dhaupert » Fri Mar 26, 2010 9:02 pm

Hi there,

Thanks for your posting. DBConvert has been around for a long time, and I'm not even sure it's up to date with our latest HanDBase format. The problem you're describing sounds more like it has to do with the database name than the file name. On the Palm, each file is actually a PDB file or a PRC file- the PRC file has code (ie, is an app). The PDB file is any data file. All HanDBase and JFile databases are PDB files. And the rule is that only one can exist with any particular name. So it sounds like when you install the HanDBase one, the JFile one is overwritten. The solution there would be to give them a different name if the DB Convert app supports that, or to rename the HandBase databases on the desktop before installing them. This is not renaming the file, this involves going into the HanDBase program and then choosing DB Properties and then General to provide a unique name.

Hope this helps!
dhaupert
 
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Re: New HDB files overwriting old Jfile DB's

Postby pjk » Sat Mar 27, 2010 1:50 am

Dave - thanks for the quick reply.

As far as the format is concerned, DBconvert asks for the path to the desktop app (ie HanDBase desktop) so I assume it gets around the version issues by actually using your own app to do with creation/population of the database. (It seems to popup momentarily during the migration)

As for filename, I'm not quite clear how you are distinguishing between "filename" and "database name".

In the configuration page for a file conversion, under "Export To", you can specify any filename you want. Originally I specified a filename with the same name as the original file (DBconvert didn't warn me about this), and understandably it overwrote the original files when hotsynced.

But in subsequent tries I changed the destination filename (ie "[OriginalDBname]_HDB.PDB", and it still overwrote the originals.

There is an option to "AutoInstall" the files to the Palm, so then I decided to disable that and just manually install the resulting "[OriginalDBname]_HDB.PDB" files to the Treo via the Palm Desktop install utility. The original files for some reason STILL got overwritten.

So it seems as if one of two things is happening. Either the HanDBase conduit is doing something (I still have to re-study the docs on how it migrates files to its own archive folder and so on so I fully understand what it actually does during a sync), or there is perhaps some metadata in the migrated database files that reference the original Jfile filenames, which causes them to be overwritten despite the fact that the new filenames are clearly different than the originals.

There is a field in DBconvert called "PDA database name", which I see now is probably the "metadata" I mentioned earlier, albeit it perhaps doesn't reference the original filename/path, just the internal representation of what the database "thinks" it's called. It certainly would be possible that this is what is happening, as I tried to duplicate those names to reduce confusion in the UI as I try to match the new HDB database functionality to the old Jfile one (given that DBConvert only migrates the basic record data), but I certainly can try making those unique and see if that helps.

Thanks,

Phil
pjk
 
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Re: New HDB files overwriting old Jfile DB's

Postby pjk » Sat Mar 27, 2010 11:00 am

I erased all the previously migrated files from both the mobile device and the export directory. I replaced the Jfile databases again, made sure they were accessible. I then re-exported to HanDBase using DBconvert, changing the "PDA Database name" attribute by adding "HDB" at the end in all the exported databases, hotsynced.

Same problem - deleted all the Jfile databases on the Treo again. :-(

The only thing I can think of at this point is that something is stupidly only parsing the initial characters of the "PDA Database name", sees the first few characters as the same, and then assumes that they are the same, and removes the original DB's.

I really didn't want to junk-up the database name with extra visible characters because of how limited the display space is on the mobile screen. I guess I could try adding an underscore at the beginning at the name or something, but this is beginning to get old...
pjk
 
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Re: New HDB files overwriting old Jfile DB's

Postby pjk » Sat Mar 27, 2010 11:26 am

It appears that DBconvert doesn't allow you to change the "PDA Database name" attribute when converting from Jfile to HDB.

Every time I try to change it, it reverts to the original string. (apparently what it is reading from the original Jfile database being converted)

So this particular issue looks like it may be a DBconvert idiosyncracy. Pity I can't get any response from the developer of that..
pjk
 
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Re: New HDB files overwriting old Jfile DB's

Postby Tomvb62 » Wed Apr 07, 2010 4:44 pm

I'm the author of the DBConvert program that you've mentioned. That the program doesn't allow to change the PDA database name is indeed a bug. I've fixed the problem in the program and uploaded the new version in the Files area of the technical support group (http://tech.groups.yahoo.com/group/fnprog2pda/). Due to recent problems with Yahoo groups our e-mails in that group disappeared. Sorry, for any inconveniences, that this might have caused you.

Cheers,Tom
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Re: New HDB files overwriting old Jfile DB's

Postby dhaupert » Fri Apr 09, 2010 8:09 am

Hi Tom,

Thanks for posting your update info here and thanks for the work you've done on DBConvert!
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