Web DBI - Concurrent editing
	l How to prevent updates overwriting each other? l You can use Optimistic Locking via 'qualified update': update table set ...=... where  key = $old_key and field1 = $old_field1 and field2 = $old_field2 and … for all fields n Potential problems with floating point data values not matching n Some databases support a high-resolution 'update timestamp' field that can be checked instead l Check the update row count n If it's zero then you know the record has been changed or deleted by another process
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