Archives of the TeradataForum
Message Posted: Tue, 20 Dec 2005 @ 10:56:09 GMT
| Subj: | | Re: NULLS to Spaces |
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| From: | | Stover, Terry |
You might try embedding coalesce statements in a new base view accessed by users. Then you could retain the original view that shows nulls and
you don't have to worry about ETL changes or impacting existing applications. The coalesce's may not be that big a performance hit if the users
are doing multicolumn lookups and some of the other columns are reasonably selective. This is a good first step regardless of final resolution
because it's quick and you can track the usage in the DBQL. Many times users will complain about a problem that's more anecdotal than critical.
You may find the affected user base is small enough that a little bit of handholding will resolve the "crisis".
If you need to convert the data I wouldn't try doing an update especially if the PI is affected. Do an insert into an empty table replacing
the nulls with spaces, then rename the tables. That always gives a good rollback & QA checkpoint.
At a higher level it sounds like the tables may be seriously denormalized (100 nullable columns?) and a redesign may be appropriate.
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