Please help for a beginner

[ma...@pi.ingv.it]

Dear all,
I have just come to OJB, and it was my intention to use ODMG.
Is there any tutorial?

I would like to retrieve a collection of objects from a relational
database (Postgres), making a selection using non standard database
functions (postgis extension).
I was wondering:
1) if this is possible with ODMG?
2) if the above is possible, then what is the configuration I should make
up, and what the query should look like?

Thank you,
Francesco.




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Re: Please help for a beginner

[Armin Waibel <ar...@apache.org>]

Hi Francesco,

martinelli@pi.ingv.it wrote:
> Dear all,
> I have just come to OJB, and it was my intention to use ODMG.
> Is there any tutorial?
>

A simple odmg tutorial can be found in 'tutorial'-section
http://db.apache.org/ojb/docu/tutorials/odmg-tutorial.html


> I would like to retrieve a collection of objects from a relational
> database (Postgres), making a selection using non standard database
> functions (postgis extension).
> I was wondering:
> 1) if this is possible with ODMG?

No, this is not supported. To use specific sql-extension or functions 
you have to use plain SQL. It's possible to use plain SQL within the 
odmg-api using the underlying PB-api
http://db.apache.org/ojb/docu/guides/odmg-guide.html#Access+the+PB-api+within+ODMG
http://db.apache.org/ojb/docu/faq.html#performSQL

But why do you want to use OJB to read the data? It seems that the 
PostGIS jdbc extension can return java geometry objects
http://postgis.refractions.net/docs/ch04.html#id2453247

regards,
Armin

> 2) if the above is possible, then what is the configuration I should make
> up, and what the query should look like?
> 
> Thank you,
> Francesco.
> 
> 
> 
> 
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> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
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> 

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