Fetch Join Error

fooBar12121212 · **Joined:** Fri Feb 12, 2010 12:53 pm **Posts:** 1

I want my loads to perform joins instead of selects. I have read the documentation and have tried to configure my classes to load using joins, but the logs show they are using selects.

VesselStack has an ISet of VesselSpot
VesselSpot has an ISet of VesselTelemetry

When performing a load of VesselStack I see multiple selects in the logs instead of one select with outer joins.

Any suggestions on why this is not working?

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
  <session-factory>
    <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
    <property name="dialect">NHibernate.Dialect.Oracle10gDialect</property>
    <property name="connection.connection_string">User ID=Foo;Password=Bar;Data Source=fooBar</property>
    <property name="connection.driver_class">NHibernate.Driver.OracleClientDriver</property>
    <property name="connection.isolation">ReadCommitted</property>
    <property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
    <property name="max_fetch_depth">4</property>
    <property name="show_sql">true</property>
  </session-factory>
</hibernate-configuration>

Code:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="Server"
                   namespace="Model"
                   default-cascade="save-update">

  <class name="VesselStack" table="VESSEL_STACK" dynamic-update="true">
    <id name="VesselStackId" column="VESSEL_STACK_ID">
      <generator class="uuid.hex" />
    </id>
    <property name="BayIso" column="BAY_ISO"/>
    <property name="StackIso" column="STACK_ISO"/>
    <set name="VesselSpots" table="VESSEL_SPOT" inverse="true" cascade="all" fetch="join" lazy="false" sort="VesselSpotComparer">
      <key column="VESSEL_STACK_ID" />
      <one-to-many class="VesselSpot" />
    </set>
  </class>

  <class name="VesselSpot" table="VESSEL_SPOT" dynamic-update="true">
    <id name="VesselSpotId" column="VESSEL_SPOT_ID">
      <generator class="uuid.hex" />
    </id>
    <property name="SpotIso" column="SPOT_ISO"/>
    <set name="VesselTelemetries" table="VESSEL_TELEMETRY" inverse="true" cascade="all" fetch="join" lazy="false" sort="VesselTelemetryComparer">
      <key column="VESSEL_SPOT_ID" />
      <one-to-many class="VesselTelemetry"/>
    </set>
    <many-to-one name="VesselStack" class="VesselStack" column="VESSEL_STACK_ID" cascade="save-update" fetch="join" lazy="false" not-null="true"/>
  </class>

  <class name="VesselTelemetry" table="VESSEL_TELEMETRY" dynamic-update="true">
    <id name="VesselTelemetryId" column="VESSEL_TELEMETRY_ID">
       <generator class="uuid.hex" /> 
    </id>
    <property name="ResultBayIso" column="RESULT_BAY_ISO"/>
    <property name="ResultStackIso" column="RESULT_STACK_ISO"/>
    <property name="ResultTierIso" column="RESULT_TIER_ISO"/>
    <many-to-one name="VesselSpot" class="VesselSpot" column="VESSEL_SPOT_ID" cascade="save-update" fetch="join" lazy="false" not-null="true"/>
  </class>
  
</hibernate-mapping>

wolli · **Posted:** Sat Feb 13, 2010 6:15 am

How do you load ? If you use a HQL query the fetch mode in the mappaing is ignored. YOu have to spefify it directly in the query.

from VesselStack st left join fetch st.VesselSpot sp left join fetch sp.VesselTelemetry