Wednesday, July 19, 2006

Data Mover gets an IQ upgrade

Data Mover was designed for a simple data set, where new records were added, and old records changed. Deleted records were to be marked as deleted, not actually deleted. Or if they were deleted, you had to delete them in both source and target data sets.
Of course the inevitable happened: deletions got out of synch, and we ended up spending hours adding records that should have been deleted already, only to delete them again. This turns out to be a great way to waste a lot of time and bandwidth for no reason.
Last night I finally added some intelligence to the process. There is now a parameter to tell Data Mover not to add any records older than a certain date, say 1 month old. This doesn't affect changed records, only ones to be added. Since the parameter applies to the entire dataset, it's easy to disable it if a new data take-on is required. It only affects the SYNx keywords, so a normal APPEND or UPDATE query is not tampered with in any way.
Data Mover is a utility that is used to process, convert or synchronize application data. At present I am using it to keep data from around 2 dozen Access97 satellite sites synchronized with a head office SQL Server database. Both the satellites and the head office can make changes to the data, subject to certain conditions.

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