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Message Posted: Wed, 16 Mar 2005 @ 18:28:54 GMT
<-- Anonymously Posted: Wednesday, March 16, 2005 13:11 -->
I'm new in Teradata and have many doubts about indexes.
One of this doubts, is the use of key tables when joining large tables with diferent primary indexes. What is exactly the purpose of using key tables? Any Examples?
The second doubt i=B4ve got is the selection of the primary index. For example i have detected that many of de querys that my customer performs against teradata is using one field (access_method_id). When i create the primary index using this field as NUPI, one of amps starts to work slower than the others, the reason i have found about this is thar there are too many null values.
Is there any way to keep the primary index on this column but discard the nulls?
What documentary do you recommend?
Thanks in advance.
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