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From "Patrick Linskey" <plins...@bea.com>
Subject RE: possible to write a JPA Query to that filters both an Entity and its relationship entities?
Date Fri, 23 Feb 2007 22:30:25 GMT
> is this (using separate  DTOs) the common practice to handle the 
> scenario where your view differs from your entity model?

Yes. Without decent ORM, you always have to create a DTO model. With
decent ORM, you have the option of making your DTO model and your
persistent domain model the same actual classes. This is useful from a
productivity standpoint, but can quickly break down in situations like
this.

SDO is a bit different than JPA / ORM, since it is really addressing the
problem of data transfer. So it includes a few concepts that aren't
directly covered in strict ORM.

-Patrick

-- 
Patrick Linskey
BEA Systems, Inc. 

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> -----Original Message-----
> From: Tom Mutdosch [mailto:tommut@gmail.com] 
> Sent: Friday, February 23, 2007 2:24 PM
> To: open-jpa-dev@incubator.apache.org
> Subject: Re: possible to write a JPA Query to that filters 
> both an Entity and its relationship entities?
> 
> True.  In this case, I guess I'd rather lean towards the side 
> of "best 
> practice".  It sounds like in your estimation (and I see 
> there are tons 
> of discussions about this after doing a quick search) that 
> would be to 
> keep this separated into another type of wrapper object and keep my 
> Entities pure.  That sounds reasonable. 
> 
> I don't come from a Hibernate background, but is this (using separate 
> DTOs) the common practice to handle the scenario where your 
> view differs 
> from your entity model? 
> Thanks,
> Tom
> 
> Patrick Linskey wrote:
> > You could do that, but personally, I tend to be wary of 
> putting computed
> > data into the entity types themselves. You're in the grey 
> area in the
> > question of when to use your domain model as a DTO graph 
> vs. creating a
> > separate set of DTOs.
> >
> > -Patrick
> >
> >   
> 
> 

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