Hi All,



I need some advice on how to structure my table for speed, but without
creating a redundant field hopefully.



I need to see the latest communication for a customer. Problem is, the
customer ID is not in the communications table, but is instead linked
via an incidents table.



So, I can't create an index on communications involving the customer ID.
And if I put the customer ID into the communications table, then I run
the risk of a communication belonging to customer A, and also to an
incident which belongs to customer B, due to my database no longer
following a normalised model.



I thought maybe "computed by" was the thing to use, so I looked it up in
Helen's trusty Firebird Book, but I see she warns against doing just
that for this kind of thing (plus the book says the field won't be able
to be indexed anyway)



I'm thinking I'm going to have to create the redundant field and update
it with triggers, but was wondering whether this wasn't a common
problem, with a simple solution that I'm just missing.



Thanks!

Maya



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