As stated earlier, the Business Components from Tables Wizard in JDeveloper automatically creates associations between entities that represent tables that are joined by a foreign key constraint. Associations are like master–detail relationships in a relational database. However you can also create an association manually, as follows:
1. Right-click the package name.
2. Select New Association from the Context menu.
This displays the Create Association Wizard.
Viewing the Components of an Association
When you select an association in the Application Navigator, the Structure window displays the source (master) entity and the destination (detail) entity. In this example, the PersonEO entity is the source in the association and the OrderEO entity is the destination. That means that each person can have multiple orders, and that every order must belong to one person.
JDeveloper generates only one file for each association: <Association>.xml (for example, OrdersPersonsFkAS.xml), which contains all the metadata for the association.