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Re: Weird problem with setPrefetchingRelationshipKeyPaths
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Re: Weird problem with setPrefetchingRelationshipKeyPaths


  • Subject: Re: Weird problem with setPrefetchingRelationshipKeyPaths
  • From: Chuck Hill <email@hidden>
  • Date: Mon, 17 Mar 2008 09:59:52 -0700

HI Miguel,


On Mar 16, 2008, at 11:32 AM, Miguel Arroz wrote:

I have an entity A where each object contains some references to other objects in entity B (each A contains some Bs, but each B is on a diferente relation). The relations are one-to-one, and are modeled only from A to B.

That last part _might_ be the problem.


I'm fetching some objects from entity A, and I'm using setPrefetchingRelationshipKeyPaths to pre-fetch the Bs. I'm passing in an array with all the relationship keys I want to grab.

I run this, and it looks like it's going to work. The A SELECT query is done, and then some SELECT DISTINCT queries are done on the B table, fetching the related B objects. I copied one of those querie from the log to the DB console and run it, and it does in fact select the objects that it's supposed to.

So far, looks good. The problem is that when I later iterate among the fetched A objects and start to access Bs, the Bs are all fetched again, each one in it's roundtrip.

I fired up the debugger, and something really strange happens. After all those queries being done, I peek inside an A object, and find that Bs are not being placed in As. IE, all the relationship to Bs are still faults, not real data.

So, EOF is fetching the objects, but it's not inserting them on the graph... why?


I don't know. But I recently noticed that one place in the project I am working on has the same problem. It is on my list to investigate. If you figure it out, us know.

Chuck

--

Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects






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References: 
 >Weird problem with setPrefetchingRelationshipKeyPaths (From: Miguel Arroz <email@hidden>)

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