OUTER JOIN to Secondary Table

[ashakirin]

Is it any way in EclipseLink to make OUTER JOIN to Secondary Table?

Use case: There is 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 (@SecondaryTable), 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.

Unfortunately I cannot find acceptable solution in Internet.
Is INNER JOIN for Secondary Table fixed by design?

Regards,
Andrei.

[Andrei Shakirin]

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Hello,

 

Is it any way in EclipseLink to make OUTER JOIN to Secondary Table?

Use case: There is 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 (@SecondaryTable), 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.

I cannot use OneToOne relation for this case, because mapping is defined directly for one business domain object.

Here's example code:

 

@Entity @Table("EMPLOYEE") @SecondaryTable("EMPLOYEE_EXTRA", pkJoinColumns=@PrimaryKeyJoinColumn(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

 

}

 

Unfortunately I cannot find acceptable solution for it.
Is INNER JOIN for Secondary Table fixed by design?

Regards,
Andrei.

 

 

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[Andrei Shakirin]

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Hello,

 

Is it any way in EclipseLink to make OUTER JOIN to Secondary Table?

Use case: There is 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 (@SecondaryTable), 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.

Unfortunately I cannot find acceptable solution in Internet.
Is INNER JOIN for Secondary Table fixed by design?

Regards,
Andrei.

                

 

 

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eclipselink-users mailing list
eclipselink-users@...
https://dev.eclipse.org/mailman/listinfo/eclipselink-users

[James Sutherland]

Normally if an outerjoin is desired, you should instead use a OneToOne relationship instead of a multiple table mapping.  The issue is just not in reading the class, but updating or inserting a row that may not be there is problematic.

If you must use a multiple table mapping, then you can use a DescriptorCustomizer to set the multipleTableJoinExpression for your descriptor to one using equalOuterJoin.

Another solution would be to define a view that does the other join and map to it.

See also,
http://en.wikibooks.org/wiki/Java_Persistence/Tables#Multiple_table_outer_joins

ashakirin wrote:

Is it any way in EclipseLink to make OUTER JOIN to Secondary Table?

Use case: There is 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 (@SecondaryTable), 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.

Unfortunately I cannot find acceptable solution in Internet.
Is INNER JOIN for Secondary Table fixed by design?

Regards,
Andrei.