one-to-many using same Class

mcueh · **Joined:** Wed May 05, 2004 3:26 am **Posts:** 25

Hibernate version 2.1.3
Mapping document

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping package="de.gloegl.road2hibernate">   

 <class name="Port" table="fromto"> 
        <id name="id"  column="id"  type="java.lang.String"  unsaved-value="null"  length="32"> 
            <generator class="hilo"/> 
        </id> 

      <property name="abbreviation" column="originID" not-null="true"/> 
        <property name="name" column="origin" not-null="true"/> 

        <many-to-one name="origin"  class="Port"  column="destinationID"  cascade="none"  not-null="false"/> 

        <set name="destinations"  table="fromto"  cascade="all"  inverse="true" lazy="false"> 
            <key column="originID"/> 
            <one-to-many class="Port"/> 
        </set> 

    </class>
</hibernate-mapping>

Table structure [fromto]

Column_name
--------------
id
origin
originID
destination
destinationID

Requirement
To map every origin with a distinct origindID to all corresponding destinations

---------
I'm not sure whether the mapping is correct. When I try to execute the HQ "from Port" I get the following

Code:

WARN  - SQL Error: 102, SQLState: 42000
ERROR - Incorrect syntax near 'left'.

WARN  - SQL Error: 102, SQLState: 42000
ERROR - Incorrect syntax near 'left'.

ERROR - could not load: [de.gloegl.road2hibernate.Port#AXL]
com.sybase.jdbc2.jdbc.SybSQLException: Incorrect syntax near 'left'.

Thanks in advance :(

mcueh · **Joined:** Wed May 05, 2004 3:26 am **Posts:** 25

Ok, I have changed the mapping to look like the following

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping package="de.gloegl.road2hibernate">   

<class name="Port" table="fromto"> 
        <id name="id"  column="id"  type="java.lang.String"  unsaved-value="null"  length="32"> 
            <generator class="increment"/> 
        </id> 

      <property name="abbreviation" column="originID" not-null="true"/> 
        <property name="name" column="origin" not-null="true"/> 
        
        <many-to-one name="origin"  class="Port"  column="originID" insert="false" update="false" cascade="none"  not-null="false"/> 

        <set name="destinations"  table="fromto"  cascade="all" inverse="true" lazy="false"> 
            <key column="destinationID"/> 
            <one-to-many class="Port"/> 
        </set>
</class>
 
</hibernate-mapping>

I can see the query from the log executing correctly

Code:

select port0_.id as id, port0_.originID as originID, port0_.origin as origin from fromto port0_ where (destinationID!='~~~' )

and calling size in the results List, comes up with the correct number, but when looking inside the results List, all elements are 'null' therefore getting a NPE.

Any help much appreciated...