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Re: when is derived column resolved
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Re: when is derived column resolved


  • Subject: Re: when is derived column resolved
  • From: Paul Hoadley <email@hidden>
  • Date: Wed, 13 Jan 2016 11:08:19 +1030

Hi Ted,

On 13 Jan 2016, at 10:39 am, Theodore Petrosky <email@hidden> wrote:

1. should I go back to creating a method on Entity Person fullName that returns a string concatenating first and last names?

Probably, yes.

OK, that’s a plan, when do you feel it’s appropriate to use a derived column?

I am reasonably sure we use them nowhere. I think you would want to limit their use to read-only attributes (or you will immediately hit the freshness issue you’ve already discovered), and quite probably to transformations that are better done in the database than in Java. (Pulling an example out of the air: maybe some kind of geospatial result that you can get from PostGIS. But even then, if you can write to the columns the result depends on, you’ve got a problem again.) Does anyone have a solid use case for derived attributes that they actually use in the real world?


-- 
Paul Hoadley
http://logicsquad.net/



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 >when is derived column resolved (From: Theodore Petrosky <email@hidden>)
 >Re: when is derived column resolved (From: Paul Hoadley <email@hidden>)
 >Re: when is derived column resolved (From: Theodore Petrosky <email@hidden>)

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