Hi Venu,
If you don't have any kind of last modified date in your source data then an incremental load is going to be tricky to do. Is it possible to get a date stamp added to the source data? If you can not modify the data structure directly to add a last updated date you could potentially add a trigger to write one? If the trigger wrote a record to an audit trail table giving the ID of the record and the time modified that could be used (along with an INNER JOIN) to give just the records you want. If you don't have a unique ID on the record either then you will need to record all of the fields that are required to uniquely identify that record - all of these can then be used in the INNER JOIN to the trigger generated table.
If you do need multiple values to uniquely identify the record then you will need to concatenate those into a single field when loading the data into QlikView - as the WHERE EXISTS (a critical component of most incremental loads) statement requires this single unique field.
Note, that for an incremental to be worth doing all loads from QVD should be optimised - otherwise there is not much point to making the load incremental.
I have blogged on both Incremental Loads and Optimised Loads in the past. I shall post a link to this thread.
Regards,
Steve
