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Message Posted: Fri, 19 Apr 2002 @ 16:17:38 GMT

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Subj:   Re: Nulls in a composite Primary Key deployed as a Primary Index
From:   Claybourne L. Barrineau

Teradata encourages that physical data model design (including index selection) should be dictated by data demographics and usage. In this way, many of us have Primary Indexes which differ from primary keys (a notion which other database users cringe at.)

Weigh the pros and cons, if the pros overweigh the cons, go ahead and include a nullable field as part of your composite primary index. Teradata made it possible; therefore, one would assume they envisioned various legitimate reasons to do so.

We work with lots of data sources from thrid-parties, I feel your pain. Work-arounds such as default values and surrogate keys can often complicate matters. Nullable fields in your composite primary index will cause some performance degradation, but its probably beats than the alternate.

My 2 Cents,

Claybourne Barrineau

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