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Re: Delete on cascade question
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Re: Delete on cascade question


  • Subject: Re: Delete on cascade question
  • From: Chuck Hill <email@hidden>
  • Date: Mon, 27 Nov 2006 10:15:42 -0800

Hi Miguel,

On Nov 27, 2006, at 9:40 AM, Miguel Arroz wrote:

I have a complicated graph of objects I want to delete. Basically almost all of them deletes the next ones on cascade. So, imagine A. A has a lot of Bs. Each B has a lot of Cs. Each C has a lot of Ds, and so on. On a moderate size example, I'm talking about 5000 objects or more.

Even if I choose the delete on cascade option in EOModeler, the generated SQL will not have the DELETE CASCADE code, so I guess it's all done by WO.

Yes. It has to fetch each object it deletes so that it can call validateForDelete on it. It does this to maintain the consistency as set in your model and code.



And that means... it's terribly slow.

Yes, it can be.


So here's my two questions:

1) Is there a way to make EOModeler generate the DELETE CASCADE SQL?

No. That would violate EOF's goal of maintaining consistency and enforcing rules.



2) Adding it to the database definition (either EOModeler or manually) will conflict with EO in any way?

It may. If the objects being deleted have been fetched, then EOF will not be aware that they are gone. This is the same situation that you would face if you were running multiple instances and EOF processed the deletion. It is a situation that you need to handle anyway.


So what it comes down to is do you need speed or validateForDelete more?


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: 
 >Delete on cascade question (From: Miguel Arroz <email@hidden>)

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