Configuring Bidirectional Relationship

If a mapping has a bidirectional relationship in which the two classes in the relationship reference each other with one-to-one mappings, then set up the foreign key information as follows:

• One mapping must call the setForeignKeyFieldName method.

• The other must call the setTargetForeignKeyFieldName method.

It is also possible to set up composite foreign key information by calling the addForeignKeyFieldName and addTargetForeignKeyFieldName methods. Because TopLink enables indirection by default, the attribute must be a ValueHolderInterface.

Note: When your application does not use a cache, enable indirection for at least one object in a bidirectional relationship. In rare cases, disabling indirection on both objects in the bidirectional relationship can lead to infinite loops.

Table 35-18 summarizes which mappings support this option.

Table 35-19 Mapping Support for Mutable Mappings

Mapping	Using TopLink Workbench	Using Java
Relational Mappings
One-to-One Mapping
One-to-Many Mapping
Many-to-Many Mapping
EIS Mappings
EIS One-to-One Mapping
EIS One-to-Many Mapping

Using TopLink Workbench

To maintain a bidirectional relationship for a mapping, use this procedure:

1. Select the mapped attribute in the Navigator. Its properties appear in the Editor.

2. Click the General tab. The General tab appears.

   Figure 35-18 General tab, Maintains Bidirectional Relationship option

   
   Description of "Figure 35-18 General tab, Maintains Bidirectional Relationship option"
   
   

Use this table to enter data in the following fields on the tab:

Field	Description
Maintains Bidirectional Relationship	Specify if TopLink should maintain the bidirectional link for this relational mapping.
Relationship Partner	Select the relationship partner (from the list of mapped attributes of the Reference Descriptor) for this bidirectional relationship.