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Re: [eclipselink-users] loading collection problem 
Hi Tom,
Named query: select l from Lamp l left join fetch l.gears where l.id = :lampId 

This is the SQL:
SELECT t1.ID, t1.PRODUCT_TYPE, t1.CODE, t1.SHORT_CODE, t1.NAME, t1.family_id, t0.ID, t0.PRODUCT_TYPE, t0.CODE, t0.SHORT_CODE, t0.NAME, t0.family_id, t0.GEAR_TYPE, t2.ID, t2.CODE, t2.NAME, t2.PROD_CAT FROM PLI_LAMP_GEAR t3, PLI.PLI_INDUSTRIAL_FAMILIES t2, PLI.PLI_CATALOG_PRODUCTS t1, PLI.PLI_CATALOG_PRODUCTS t0 WHERE (((t1.ID = ?) AND (t1.PRODUCT_TYPE = ?)) AND ((((t3.lamp_id (+) = t1.ID) AND (t0.ID (+) = t3.gear_id)) AND (t0.PRODUCT_TYPE = ?)) AND (t2.ID = t1.family_id))) 
   bind => [75159, Lamp, Gear]

A Product has a @JoinFetch to an IndustrialFamily
When I remove the "left join fetch l.gears" from the named query, a Lamp with its Family is returned 

Database: Oracle 10G XE
jdbc brand version: 10.2.0.4/ojdbc14.jar

Leon

Tom Ware wrote:

Hi Leon,

  Can you post the generated SQL?

  Also, can you post your database and jdbc driver brand and version?

Thanks,
Tom

Leon Derks wrote:

Hi Tom,
When I run the SQL against my database it also doesn't return something. So that is correct. 

I think I have to change my named query, but don't know how.
I want to load a Lamp object with its collection of gears. If it has no gears, then the collection has to be empty. 
The query I run now, return no Lamp at all.

Leon



Tom Ware wrote:

Hi Leon,
What SQL is your query producing? If you run the SQL against your database, does it return a result?
To see the SQL, you can increase the logging level. I suggest using the maximum logging level when debugging. To do that, specify the persistence unit property in your persistence.xml 

<property name="eclipselink.logging.level" value="FINEST"/>

-Tom

Leon Derks wrote:

Hello

Thanks for the answer on my previous question. That works well!

But now I have another problem.
I want to load an object with a collection that may be empty.

For example my Lamp object has a @ManyToMany relation with Gear.

public class Lamp extends Product {

   @ManyToMany
@JoinTable(name="PLI_LAMP_GEAR", joinColumns = @JoinColumn(name="lamp_id", referencedColumnName = "ID"), inverseJoinColumns = @JoinColumn(name="gear_id", referencedColumnName = "ID")) 
   private List<Gear> gears = new ArrayList<Gear>()

}

public class Gear extends Product {
}
In my situation, the Lamp has no Gears, so the join table is empty for this lamp.
But when I try to load the Lamp it returns nothing. I want it to return a Lamp (with name, description etc) and an empty collection of Gears.
This is my named query: "select l from Lamp l left join fetch l.gears where l.id = :lampId"
I tried several queries, but always get the message: "javax.persistence.NoResultException: getSingleResult() did not retrieve any entities." 

Am I doing something wrong?

greetings,
Leon

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