Home » Modeling » EMF "Technology" (Ecore Tools, EMFatic, etc) » [TEXO] traverse object graph
| [TEXO] traverse object graph [message #873587] |
Fri, 18 May 2012 15:41  |
 Gary Godfrey
Messages: 31
Registered: February 2012 |
Member |
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Hi,
Is there a way to traverse back up through the JPA annotated TEXO generated domain model?
e.g.
Application (id, channel, product)
--->Applicant(s) (id, first name, last name, type)
------>Address(s) (id, line1, line2, type)
The data is persisted to the datastore fine. JPA adds parent id column to the child tables when the schema is auto-generated.
I now have the challenge of querying the data. The user wants the following data returned:
application.id, application.channel, address.line1, applicant.firstname where address.type = "home" and applicant.type = "gold";
The equivalent SQL would be something like this; joining to each parent table to get the attributes required:
select a.id, a.channel, b.firstname, c.line1, from Application a, Applicant b, Address c where c.type = "home"
and b.type = "gold"
and c.id = b.id
and b.id = a.id;
I can use the ModelPackage to validate that address.line1 is a valid EAttribute. I cannot though see how I can traverse back up the object graph to find the parent structure right up to my top-level domain object. Is this possible?
Thanks,
Gary
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| Re: [TEXO] traverse object graph [message #873598 is a reply to message #873587] |
Fri, 18 May 2012 16:08  |
Martin Taal
Messages: 5468
Registered: July 2009 |
Senior Member |
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Hi Gary,
You have to explicitly model the pointer to the parent in your model, you can make the association bidirectional. Texo
should map this correctly. See also this wiki page:
http://wiki.eclipse.org/Texo/Code_Generation_Patterns#Generation_of_a_safe_bi-directional_association_API_.28or_not.29
gr. Martin
On 05/18/2012 05:41 PM, Gary Godfrey wrote:
> Hi,
>
> Is there a way to traverse back up through the JPA annotated TEXO generated domain model?
>
> e.g.
>
> Application (id, channel, product)
> --->Applicant(s) (id, first name, last name, type)
> ------>Address(s) (id, line1, line2, type)
>
>
> The data is persisted to the datastore fine. JPA adds parent id column to the child tables when the schema is
> auto-generated.
>
> I now have the challenge of querying the data. The user wants the following data returned:
>
> application.id, application.channel, address.line1, applicant.firstname where address.type = "home" and applicant.type =
> "gold";
>
>
> The equivalent SQL would be something like this; joining to each parent table to get the attributes required:
>
> select a.id, a.channel, b.firstname, c.line1, from Application a, Applicant b, Address c where c.type = "home"
> and b.type = "gold"
> and c.id = b.id
> and b.id = a.id;
>
>
> I can use the ModelPackage to validate that address.line1 is a valid EAttribute. I cannot though see how I can traverse
> back up the object graph to find the parent structure right up to my top-level domain object. Is this possible?
>
> Thanks,
> Gary
--
With Regards, Martin Taal
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