Using TPacketDataSet delta to write cached updates to ISAM database record. Using Modified Record pair, The second delta record marked usModified holds every field, with the unmodified fields carrying NULL as the NewValue. Question: How can I determine which fields carry NULL value because they were deliberately changed to NULL, and which fields are NULL because they wern't changed? Simply writing NewValue to the persistence layer would result in clearing all field values which were not changed. Al.
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