Locking Paradox databases in multi-user network environment


Locking of database files in network environment is important for their consistency. If two or more users would be able to simultaneously write to the same database table, they could not be aware of updates to the table some other user has made. Only the changes from the last user who saved the label are preserved and all previous are ignored.


As a solution to these problems Paradox introduces special locking mechanism that has its use in network environments. It is network control file, PDOXUSRS.NET.

The net file contains the users currently using the BDE (Borland Database Engine) and which table they're accessing. This is how NiceLabel knows which tables are in use by other users and will not allow you to alter them simultaneously. It also serves as the reference point for all lock files created by Paradox. Each lock file references the network control file and contains information regarding the locks on the table and by which user. It is vital that each user maps to the same network control file.

How to map to the network control file?

  1. Go to Start ->Programs -> NiceLabel and start BDE Administrator.
  2. Select Configuration tab.
  3. Select Drivers, then Native and lastly Paradox.
  4. Select NET DIR and browse the directory, where PDOXUSRS.NET resides for your network.

Please note! Every user in your network should set NET DIR to the same directory.

If a network file server stores databases, this set-up will be enough. But if databases are stored on some workstation computer, that shares them to other computers but accesses them as well, one further modification in BDE Administrator will have to be made.

  1. Start BDE Administrator one more time.
  2. Select Configuration tab.
  3. Select System, then INIT.
  4. Select LOCAL SHARE parameter and change it to TRUE.

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