Adding a Computed Column to a Table (2) - SQL School Video

• Andy Warren

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  June 16, 2009 at 12:18 pm

  #222623

  Comments posted to this topic are about the item Adding a Computed Column to a Table (2) - SQL School Video

  Andy
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• mikelawton

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  June 25, 2009 at 8:56 am

  #1015358

  Hi Andy,

  I'm curious to whether you'd recommend this approach for a particularly gnarly database I've inherited. It uses a concept of "partial text" for it's keys. For example, 2007-000123-001 might be the key in a table. The first 11 characters is, in essence, the primary key of the parent table in a parent-child hierarchy. The -001 makes it unique in the child table and also gives it a sequential order.

  As you can imagine, it's painful because searches invariably rely upon substrings or LIKE clauses. I know that's killing the performance.

  My thought was that I could use this computed column approach to slowly migrate us out of this hell, while still maintaining legacy support. I'd be curious to hear your thoughts.

  Great work!

  -Mike L

• Peter Cronin

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  June 25, 2009 at 12:40 pm

  #1015547

  I was wondering what the performance advantages are between a derived field in a view and computed field in a table. Would you do one over the other because one performs better?