Forums

by tyc >> Tue, 29 Apr 2003 9:17:33 GMT

Dear Jade Developers,

We met with some questions that we hope to find out the answers to
better our understanding of Jade.

1) If the combo box list a transient collection and the transient collection was deleted at the end of the method, when you click the
combo box, there will be an error (4 Object not found), we had not
found the error before loaded the Jade release 278, moreover, the
method DisplayCollection of table had the same problem.

2) First, I opened a MDI form e.g A form and make it maximal, then I opened a MDI form which is normal state, then the A form will also be changed to normal state. Can I know why it is like so?


3) I know Jade can distribute the database to multi hard disk
partition in database server by defined different Map file in
different path, but i don't know whether Jade can distribute database
to multi PC and whether a map file (only included a class) can be distributed to multi PC.

4) Can I know what is maximal size of the log file?

5) I used the Jade Online Database Backup utility to backup the
database, how to use the data backuped to a new or existing system? is
it that we will use the Jade Database Utility? I used it to recover database using the data backuped, after did it, there is an error
which seems like to be about the CheckSum error, how to process it?


Any advise appreciated.

Regards,
L.C. Lim

by Patwos >> Tue, 29 Apr 2003 22:13:33 GMT

1) I wouldn't have thought this would be new in the 278 release, but regardless if you're using a transient to populate via listCollection or displayCollection you should make sure the transient collection survives for the lifetime of the form to prevent this error 4 from occurring. In this situation I'll often make the collection an exclusive reference on the form to ensure it survives for the lifetime of the form and to ensure it's automatic deletion on the unload of that form.

2) This is standard windows MDI behaviour and happens for me with other true MDI applications - note that MS Office applications use simulated MDI not the standard windows MDI.

3) You'll find that as of the 5.2 release you cannot use a network drive for the recovery logfiles and it wouldn't surprise me if in future the people at Jade decide to enforce a similar restriction on the database files as well. Especially given that other serious db manufacturers have similar restrictions, no doubt due to the significantly increased risk of data loss as you're introducing a whole layer of network redirectors etc into the mix for your database writes. For this reason alone I would never use a standard mapped network drive for any database files, Jade or otherwise.

4) You haven't indicated which logfile you're referring to, but a number of them can be configured via the relevant ini file settings.

5) You haven't indicated what sort of checksum error you are getting so I'll try to cover 2 possibilities that I know of.

a) If you're getting an error on the checksum that was created during the backup process, have you performed any operations on the backup directory that would have opened the backup copy of the database in update mode and thereby negated the checksum information from the "backupinfo" file created during the backup?

b) Have you tried to recover the database with older binaries. As from the 220 consolidated there was a new checksumming feature introduced to help detect data corruption introduced at the OS or disk subsystem level - refer the release notes in the 220 consolidated and above for a detailed description of this. Is it possible your backup was from a system running 5.2.08.220 or above and you used binaries from pre 5.2.08.220 to attempt the restore/recovery?

If this doesn't help, you may want to contact the guys in Jade Support to see if they can help - they're usually pretty responsive whenever I've contacted them for assistance.

Hope that helps,
Patwos.