Hi,
You can add a custom strategy to 'employeeExtraData' field which will
force OUTER JOIN during select.
Something as follows:
1. Extend a strategy:
public class OuterJoinStrategy extends StringFieldStrategy {
public int select(Select sel, OpenJPAStateManager sm, JDBCStore store,
JDBCFetchConfiguration fetch, int eagerMode) {
field.setJoinOuter(true); // force outer join -- 'field' is a
protected
field of super class
return super.select(sel, sm, store, fetch, eagerMode);
}
}
2. plug that strategy via annotation as:
@Column(table="EMPLOYEE_EXTRA",
name="EMPLOYEE_EXTRA_DATA",nullable=true)
@Strategy(value="some.package.OuterJoinStrategy")
private String employeeExtraData;
3. change MappingDefaults to use that strategy
public class MyMappingDefaults extends PersistenceMappingDefaults {
FieldStrategy outerJoinStrategy = new OuterJoinStrategy();
public Object getStrategy(ValueMapping vm, Class type, boolean adapt) {
if
("Employee.employeeExtraData".equals(vm.getFieldMapping().getFullName(true)))
{
return outerJoinStrategy;
}
return super.getStrategy(vm, type, adapt);
}
}
4. finally Configure your mapping defaults in persistence.xml
<property name="openjpa.jdbc.MappingDefaults"
value="some.package.MyMappingDefaults"/>
It may be a mere flip of a switch to change the INNER JOIN to OUTER for
fields mapped to secondary tables, but I can not find it.
gretchch wrote:
>
>
>
> It seems to me that I can't be the only person that ever wanted an outer
> join to a secondary table, but I have spent a whole day searching the
> internet for a solution, and haven't seen one (except for a
> Hibernate-specific one). I have a main employee table that may or may not
> have some extra data populated in a related secondary table. If there is
> data in the secondary table, then I would like my Employee entity to have
> those fields filled in. If there isn't data for a given employee in the
> secondary table, then I would like my Employee entity to have nulls in
> those fields. Right now, if there's no row in the secondary table for a
> given employee, I get nothing. Is there any way to force openjpa to do an
> OUTER JOIN to the secondary table? I am using the version of openjpa that
> comes in the WebSphere 6.1 feature pack, so I believe I am constrained to
> use openjpa 1.0.1, unless someone can give me a method to replace the IBM
> supplied jars.
>
> Here's example code:
>
> @Entity
> @Table("EMPLOYEE")
> @SecondaryTable("EMPLOYEE_EXTRA",
> [EMAIL PROTECTED](name="EMPLOYEE_KEY"))
>
> public class Employee implements java.io.Serializable {
>
> private static final long serialVersionUID = -3789770304634576481L;
>
> @Column(table="EMPLOYEE_EXTRA",
> name="EMPLOYEE_EXTRA_DATA",nullable=true)
> private String employeeExtraData;
>
> @Id
> @GeneratedValue(strategy=GenerationType.IDENTITY)
> @Column(name="EMPLOYEE_KEY")
> private Long employeeKey;
>
> ...etc
>
> }
>
> Gretchen Chiaramonte
>
> Sun Certified Java Programmer
> IBM Certified MQSeries Engineer
> IBM Systems & Technology Group, Development
>
> Tel: 1-919-517-1750
> Tie: 255-1750
> email: [EMAIL PROTECTED]
>
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