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Re: EOQualifier proper fetch across to-many?
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Re: EOQualifier proper fetch across to-many?


  • Subject: Re: EOQualifier proper fetch across to-many?
  • From: Kieran Kelleher <email@hidden>
  • Date: Mon, 05 Mar 2012 20:55:17 -0500

Donald Knuth once said "premature optimization is the root of all evil" :-)

Try it out before assuming the performance is bad. If your tables have the needed indexes it should be fine.

If performance is bad, log the generated SQL and just apply whatever tools you have at your disposal for your database platform to figure out the problem (index, join buffer size, etc.)

Regards Kieran
___________________________
Sent from my iPad.


On Mar 5, 2012, at 3:43 PM, Jesse Tayler <email@hidden> wrote:

>
> is there a proper way to fetch across a to-many and not overkill the database?
>
> if I wanted to return a list of recently used venues that the user has associated with posts they have authored, I'd want a distinct return of venues, each having a post->author being the user, but this query like this would just churn on the database wouldn't it?
>
> I didn't see a "distinct" wonder fetch property either, don't I have to use something to ensure the list is returned without duplicates?
>
>        EOQualifier qual = Venue.POSTS.dot(Post.AUTHOR_KEY).eq(user());
>        ERXRestFetchSpecification<Venue> fetchSpec = new ERXRestFetchSpecification<Venue>(Venue.ENTITY_NAME, qual, null, queryFilter(), Venue.CREATED.descs(), 25);
>
> what's the best practice on that kind of fetch?
>
>
>
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