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Message Posted: Mon, 03 Aug 2015 @ 09:21:36 GMT
Technically, there's no reason why data shouldn't be loaded directly into the target table. However there are usually some downsides to that approach, it really depends on your situation and what you are trying to achieve.
For ** most ** tables being loaded:
- only changes are being loaded on a regular basis, not the entire table
- if you load directly into the target table then you potentially face a locking issue: Multiload/TPT Update will use table-level locks. Using Tpump/TPT Stream will not be as fast.
- the data may not be in the final, correct form. A lot of data loaded into a data warehouse first needs to be transformed and/or cleaned and/or validated. This cannot easily be done using the Teradata utilities as part of a direct load.
Can you work around all/any of these points? Yes you can if your desire is to have a final 'load' job which hits the target tables. But you will ** usually ** find that overall doing it that way is longer and uses more resources.
Does that help?
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