Re: [Wonder-disc] H2 plug in and self-referential relationships

[Chuck H. <ch...@gl...>]

On Aug 3, 2010, at 8:10 PM, Lachlan Deck wrote:

> On 03/08/2010, at 8:42 PM, Marius Soutier wrote:
> 
>> Hi,
>> 
>> unfortunately, this doesn't seem to help. In my unit tests I added that line right after the call to initEOF but I still get the referential integrity constraint violation errors. Is there anything else I have to add?
> 
> Yes, one thing to do initially.... post to the mailing list so everyone can contribute/benefit from the discussion. :)
> 
> Chuck will hopefully chime in ... right about.... <now == time when chuck responds>

Right on the money  :-)

Right now, the plugin does not handle self referential relationships.  In fact, it does not handle any sort of circular relationship.  It only looks at relationships between entities.  It could handle most circular relationships by also examining the keys to be inserted.  I did not need this so I left it as an exercise for the future.  Patched welcome.  :-)

That said, you should be getting an exception if delegate is getting installed properly.


Chuck


> 
>> Thanks,
>> - Marius
>> 
>> On 28.07.2010, at 21:33, Lachlan Deck wrote:
>> 
>>> Hi there,
>>> 
>>> On 28/07/2010, at 7:47 PM, Marius Soutier wrote:
>>> 
>>>> we've introduced a new entity to our EOModel that includes a self-referential relationship. Unfortunately, the H2 database does not support deferred constraints which leads to occasional foreign key constraint violation errors. Would it be possible to include a mechanism in the H2 plugin to reorder insertions of the same entity type?
>>> 
>>> The same problem exists for mysql and mssql. You'll want to take a look at Chuck's com.webobjects.eoaccess.ERXEntityDependencyOrderingDelegate.
>>> 
>>> e.g.,
>>> ERXDatabaseContextMulticastingDelegate.addDefaultDelegate(new ERXEntityDependencyOrderingDelegate());
> 
> with regards,
> --
> 
> Lachlan Deck
> 
> 
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-- 
Chuck Hill             Senior Consultant / VP Development

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