createQuery problem

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

Hi All,

Maps:

Code:

    <class name="com.db.device.NEMgmtInfo" table="nemgmtinfo" mutable="true" polymorphism="implicit" dynamic-update="false" dynamic-insert="false">
      <!--cache usage="read-write" /-->
      <id name="id" type="long" unsaved-value="0">
         <generator class="native">
         </generator>
      </id>

      <many-to-one name="sflowAgent" class="com.db.device.SflowAgent" cascade="all"/>
    </class>

    <class name="com.db.device.FlowMonAgent" table="FlowMonAgent" mutable="true" polymorphism="implicit" dynamic-update="false" dynamic-insert="false">
      <id name="id" type="long" unsaved-value="0">
         <generator class="native" />
      </id>

        <property name="ipAddress" type="com.db.device.IPV4AddressType">
           <column name="address_"/>
           <column name="mask_"/>
        </property>
        
        <property name="opState" type="com.db.device.OperationalStatus"/>
        <property name="adminState" type="com.db.device.AdminStatus"/>
        
        <property name="ipPort" column="ip_port" type="integer"/>
      <many-to-one name="pollingInterval" class="com.db.qos.valuewithunits.TimeInterval" cascade="all"/>
      <many-to-one name="samplingInterval" class="com.db.qos.valuewithunits.TimeInterval" cascade="all"/>
        <property name="useMgmtIPAddressAsFlow" type="boolean"/>
        
        <joined-subclass name="com.db.device.SflowAgent" table="SflowAgent">
         <key column="id"/>
        </joined-subclass>
        
        <joined-subclass name="com.db.device.NetFlowAgent" table="NetflowAgent">
         <key column="id"/>
        </joined-subclass>
     </class>

and trying to execute:

Code:

         q = sess.getPersistentSession().createQuery(
         "select new com.db.device.NEMgmtInfoLightweight( "+
         "nemgmtinfo.sflowAgent" +
         ") "+
         
         "from com.db.device.NEMgmtInfo as nemgmtinfo");

where

Code:

public class NEMgmtInfoLightweight extends NEMgmtInfo implements Serializable {

   public NEMgmtInfoLightweight() {
   }

   public NEMgmtInfoLightweight(
      SflowAgent sflowAgent
      ) {
      super.setSflowAgent((SflowAgent)sflowAgent);
   }

}

Surprinsingly, the generated query does not return anything from the DB (there are records in there) and NO ERROR is produced:

Hibernate:

Code:

    select sflowagent1_.id as id, 
       sflowagent1__1_.address_ as address_33_, 
       sflowagent1__1_.mask_ as mask_33_, 
       sflowagent1__1_.opState as opState33_, 
       sflowagent1__1_.adminState as adminState33_, 
       sflowagent1__1_.ip_port as ip_port33_, 
       sflowagent1__1_.pollingInterval as pollingI7_33_, 
       sflowagent1__1_.samplingInterval as sampling8_33_, 
       sflowagent1__1_.useMgmtIPAddressAsFlow as useMgmtI9_33_ 
    from nemgmtinfo nemgmtinfo0_, 
       SflowAgent sflowagent1_ 
    left outer join FlowMonAgent sflowagent1__1_ on 
       sflowagent1_.id=sflowagent1__1_.id where nemgmtinfo0_.sflowAgent=sflowagent1_.id

What's wrong here?

Please Help.

dimitry · **Posted:** Wed Mar 31, 2004 6:43 pm

Did you try execute SQL query from SQL console?
Does it produce non-empty result set?

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

dimitry wrote:

Did you try execute SQL query from SQL console?
Does it produce non-empty result set?

Thx for the answer.

I am not sure what values to provide for the arguments.

I am not a keen SQL (that's why I chose Hibernate) but it looks to me the query is trying to select from sflowagent (which is empty) instead of selecting everything from nemgmtinfo and fill in the sflowAgent attribute !

dimitry · **Posted:** Wed Mar 31, 2004 7:07 pm

Quote:

select new com.db.device.NEMgmtInfoLightweight( nemgmtinfo.sflowAgent)

Quoted part of query forces Hibernate select from sflowagent.

If you want to avoid it (select instances with sflowAgent==null), try smth like:

Code:

select new com.db.device.NEMgmtInfoLightweight(sflowAgent)
from com.db.device.NEMgmtInfo as nemgmtinfo
  right outer join nemgmtinfo.sflowAgent sflowAgent

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

dimitry wrote:

Quote:

select new com.db.device.NEMgmtInfoLightweight( nemgmtinfo.sflowAgent)

Quoted part of query forces Hibernate select from sflowagent.

If you want to avoid it (select instances with sflowAgent==null), try smth like:

Code:

select new com.db.device.NEMgmtInfoLightweight(sflowAgent)
from com.db.device.NEMgmtInfo as nemgmtinfo
  right outer join nemgmtinfo.sflowAgent sflowAgent

thx again.
Actually I want to select all nemgmtinfo instances and fill in the sflowAgent member in the obtained nemgmtinfo instances.

The suggestion above didn't do the trick.
More help, please :)

dimitry · **Posted:** Wed Mar 31, 2004 7:26 pm

Hmm..
Why you can't use simple 'select nemgmtinfo from com.db.device.NEMgmtInfo as nemgmtinfo'?

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

dimitry wrote:

Hmm..
Why you can't use simple 'select nemgmtinfo from com.db.device.NEMgmtInfo as nemgmtinfo'?

Because I don't want to pull from the db all the attributes for nemgmtinfo.

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

A question:

Why is so a problem for Hibernate to only load specific fields of an object?

It is so simple in JDO, by using fetch groups:

Query q = (Query) pm.newQuery (GroupExample.class, ...);
q.getFetchConfiguration ().addFetchGroup ("g1");
Collection results = (Collection) q.execute ();

Could we have something similar in Hibernate?

thx.

dimitry · **Posted:** Wed Mar 31, 2004 10:34 pm

What su you think about use explicit polymorphism?
http://www.hibernate.org/41.html

dia100 · **Joined:** Mon Sep 08, 2003 4:30 pm **Posts:** 203

dimitry wrote:

What su you think about use explicit polymorphism?
http://www.hibernate.org/41.html

Yeah, it's a half-way solution...
This would expand the domain model, though.

thx again.