Fetchgrups for collections

Question

Hi,
my package.jdo includes a "website" class which has a collection of "page"
class objects as an attribute. It looks something like this :
<class name="Website"
objectid-class="de.adtech.helios.WebsiteManagement.WebsiteId"
requires-extent="true" identity-type="application">
     <extension vendor-name="kodo" key="detachable" value="true" />
<field name="name" persistence-modifier="persistent"/>
<field name="pages" default-fetch-group="false"
persistence-modifier="persistent">
<collection
element-type="de.adtech.helios.WebsiteManagement.Page"/>
          <extension vendor-name="kodo" key="fetch-group" value="website_complete"
/>
</field>
<field name="id" primary-key="true"
persistence-modifier="persistent">
<extension vendor-name="kodo" key="jdbc-auto-increment"
value="true"/>
</field>
...etc
</class>
Can I do something like this ? If yes how does it behave ?
Within code I do something like this :
KodoQuery query = (KodoQuery) kpm.newQuery(entityClass);
// set fetchgroup when available
if( fetchGroup != null && fetchGroup.length() > 0)
query.getFetchConfiguration().addFetchGroup(fetchGroup);
The resulting object are than detached and returned back to the
application.
I would expect that a query without a fetchgroup added returns all
attributes and a collection of pages without attribute values but the id
of the page set (similar id field like for "website" class), so calling
the methode returning an attribute of a page within the collection returns
null.
Adding the fetchgroup "website_complete" would then return a complete
website with all attributes and all pages + attributes within the
collection.
The strange thing is that when I add the fetchgroup to the ini file
"kodo.FetchGroups=website_complete" the website is always returned
complete with attributes and pages within the collection (I guess this is
normal). When I do not add this line to the ini file but adding it to the
query there are no pages at all within the collection ...
What am I doing wrong ?
Regards,
Mark

Answer 1

Mark wrote:
Adding the fetchgroup to the Persistence Manager instead the query
seems to solve the problem.
Regards,
Mark
Hi,
my package.jdo includes a "website" class which has a collection of "page"
class objects as an attribute. It looks something like this :
<class name="Website"
objectid-class="de.adtech.helios.WebsiteManagement.WebsiteId"
requires-extent="true" identity-type="application">
     <extension vendor-name="kodo" key="detachable" value="true" />
<field name="name" persistence-modifier="persistent"/>
<field name="pages" default-fetch-group="false"
persistence-modifier="persistent">
<collection
element-type="de.adtech.helios.WebsiteManagement.Page"/>
          <extension vendor-name="kodo" key="fetch-group" value="website_complete"
/>
</field>
<field name="id" primary-key="true"
persistence-modifier="persistent">
<extension vendor-name="kodo" key="jdbc-auto-increment"
value="true"/>
</field>
...etc
</class>
Can I do something like this ? If yes how does it behave ?
Within code I do something like this :
KodoQuery query = (KodoQuery) kpm.newQuery(entityClass);
// set fetchgroup when available
if( fetchGroup != null && fetchGroup.length() > 0)
query.getFetchConfiguration().addFetchGroup(fetchGroup);
The resulting object are than detached and returned back to the
application.
I would expect that a query without a fetchgroup added returns all
attributes and a collection of pages without attribute values but the id
of the page set (similar id field like for "website" class), so calling
the methode returning an attribute of a page within the collection returns
null.
Adding the fetchgroup "website_complete" would then return a complete
website with all attributes and all pages + attributes within the
collection.
The strange thing is that when I add the fetchgroup to the ini file
"kodo.FetchGroups=website_complete" the website is always returned
complete with attributes and pages within the collection (I guess this is
normal). When I do not add this line to the ini file but adding it to the
query there are no pages at all within the collection ...
What am I doing wrong ?
Regards,
Mark