Foreign key are essential for the compiler to understand your model’s relations.
<foreign-key foreignTable = "/TheOtherTableName/" [onDelete = "cascade|setnull|restrict|none"] [onUpdate = "cascade|setnull|restrict|none"] > <reference local="/LocalColumnName/" foreign="/ForeignColumnName/" /> </foreign-key>
foreignTableThe foreign table name to refer to.onDeleteSQL on delete.onUpdateSQL on update.LocalColumnNameColumn name of the local reference.ForeignColumnNameColumn name of the foreign reference.

