[dba-SQLServer] Update query leaves null

A calculated column is a non-existent column, defined by a formula. For example, imagine a table with columns Qty, Price and Discount. A calculated column might have the formula Qty * Price * (1-Discount). This would of course require NOT NULL defintions for each column. The point is, said column virtually exists but does not physically exist. It is therefore indexable. There is no detectable speed hit (at least in my 50M sample tables).

These columns are trivial to create. Inspect the property sheet for a column and you'll figure it out.

A.

----- Original Message ----
From: JWColby <jwcolby at colbyconsulting.com>
To: dba-sqlserver at databaseadvisors.com
Sent: Monday, August 14, 2006 12:32:47 PM
Subject: Re: [dba-SQLServer] Update query leaves null

What is a calculated column?  If this is something "calculated" on the fly
what would the speed be on a 50 million row table?

John W. Colby
Colby Consulting
www.ColbyConsulting.com