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From Jakob Braeuchi <jbraeu...@gmx.ch>
Subject Re: Any plans for Reference filters?
Date Thu, 23 Sep 2004 19:49:01 GMT
hi andrew,

references are currently loaded using pb#doGetObjectByIdentity. see 
queryReferenceBroker#getReferencedObject. there's no way to use a 
query-customizer now and there might also be a problem when using proxies.

imo it should be easy to use a queryByCriteria to retrieve the referenced obj, 
but i don't know how to handle the proxy :(

jakob

Jakob Braeuchi schrieb:

> hi andrew,
> 
> the query customizer gets the parent object and the query (by criteria), 
> so it's up to the customizer to modify the query. the query is processed 
> as any other query.
> 
> jakob
> 
> Clute, Andrew schrieb:
> 
>> Yeah, looking at the code that is used for the query customizer on
>> Collections, I would assume it would be real straight forward to add
>> that to references as well.
>>
>> Now a quick question about how QC's work.
>>
>> Assume my scenario of Person with addresses collection, and the need for
>> a 'filtered' Primary Address, property named 'primaryAddress'. If I did
>> something like this:
>>
>> Sc.addEqualTo("person.primaryAddress.zipcode","90210");
>>
>> Would it be smart enough to allow the customizer to add it's filtereing
>> on the JOIN query? Does it work that way for Collections right now?
>>
>>
>>
>> -----Original Message-----
>> From: Jakob Braeuchi [mailto:jbraeuchi@gmx.ch] Sent: Thursday, 
>> September 23, 2004 2:59 PM
>> To: OJB Developers List
>> Subject: Re: Any plans for Reference filters?
>>
>> hi andrew,
>>
>> got me ! you're right query customizer only works for collections but
>> imo it should be possible for references as well. so we could have a
>> single concept for filtering.
>>
>> jakob
>>
>> Clute, Andrew schrieb:
>>
>>
>>> Can you put a query customizer on a reference descriptor? I thought 
>>> they were only for collections!
>>>
>>> -Andrew
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Jakob Braeuchi [mailto:jbraeuchi@gmx.ch]
>>> Sent: Thursday, September 23, 2004 12:59 PM
>>> To: OJB Developers List
>>> Subject: Re: Any plans for Reference filters?
>>>
>>> hi andrew,
>>>
>>> you could use a query customizer to manipulate reference queries. i 
>>> admit it's not as elegant as the filter but it's totally flexibel ;)
>>>
>>> jakob
>>>
>>> Clute, Andrew schrieb:
>>>
>>>
>>>> I have run into a couple of scenarios where it would be extremely 
>>>> helpful to be able to add additional criteria to a reference
>>>
>>>
>>> descriptor.
>>>
>>>
>>>> For instance, you might have a Person object with a collection of 
>>>> Addresses on them. Address might have a property called "Primary". 
>>>> In your query, you might want to be able to qualify to use the 
>>>> primary address. The current way to do that is to keep a foreign key 
>>>> on your person table that links back to the primacy address object, 
>>>> and update
>>>
>>>
>>>
>>>> that when your primacy address changes. So, you have both a property 
>>>> on your object, and a db column.
>>>>
>>>> It would be nice if you could still have that reference descriptor for
>>>
>>>
>>>
>>>> your person object for a Primary Address, but not maintain the foreign
>>>
>>>
>>>
>>>> key in the db, just had a certain criteria to the descriptor that 
>>>> filters it to the appropriate one.
>>>>
>>>> For instance:
>>>>
>>>> <reference-descriptor
>>>>     name="primaryAddress"
>>>>     class-ref="pojo.Address"
>>>>     refresh="true"
>>>>     auto-retrieve="true"
>>>>     auto-update="false"
>>>>     auto-delete="false"
>>>>
>>>>     <foreignkey field-ref="personPK"/>
>>>>     <foreignkey-filter value="is_primary=1"/>
>>>
>>>
>>> </reference-descriptor>
>>>
>>>> Does that make sense? Just curious if this has ever been discussed.
>>>>
>>>> Thanks!
>>>>
>>>> -Andrew
>>>>
>>>>
>>>>
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>>>>
>>>
>>>
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>>>
>>>
>>>
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>>>
>>
>>
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>>
>>
>>
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>>
> 
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