Re: Select For Update and Left Outer Join

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От Jim Nasby
Тема Re: Select For Update and Left Outer Join
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Msg-id 4F418A62-BEB6-4D77-A0F1-B8DF27F211BF@nasby.net
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Ответ на Select For Update and Left Outer Join  (Patrick Earl <patearl@patearl.net>)
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On May 1, 2011, at 12:27 PM, Patrick Earl wrote:
> In ORMs like NHibernate, there are a few strategies for mapping
> inheritance to SQL.  One of these is "Joined Subclass," which allows
> for the elimination of duplicate data and clean separation of class
> contents.
>
> With a class hierarchy such as this:
>
> Pet
> Dog : Pet
> Cat : Pet
>
> The query to get all the pets is as follows:
>
> select * from Pet
> left join Dog on Dog.Id = Pet.Id
> left join Cat on Cat.Id = Pet.Id

Since FOR UPDATE seems to be a dead end here...

Is that construct something that NHibernate natively understands? If so, could you use Postgres table inheritance
insteadof joins? 
--
Jim C. Nasby, Database Architect                   jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net




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