WinWeigh Plus Module
Replication is the process of matching and synchronizing the contents of different spatially distributed copies of a database. In this case, the different copies of the database are related to each other and their records can be modified.
With replication, changes made to the various database copies are compared and exchanged, so that all included database copies then have a consistent database again. For successful replication, all changes must be recorded in the connected copies of the database. The transaction log file is often evaluated for this purpose. In this file the database operations for the respective database are logged. The operations are then repeated for replication on the target platform. In most products that offer a replication mechanism as standard, this technique is used. This technique cannot be used with WinWeigh Plus and the SQL database server used, Interbase, because Interbase does not require a transaction log file due to its multigeneration architecture and therefore this is not available for replication. Database triggers are used to save data changes to a log table for replication the moment they occur. This method is much more flexible and can be implemented across platforms, since the procedural language of the server platform is used. InterBase triggers work very fast, so that the usual counter-argument for this type of protocol, lack of performance, does not apply.
The programming of the triggers may already include rules for the data to be replicated. Thus, the standardized replication of WinWeigh Plus can be adapted to specific projects.