Figure 5From: Critical evaluation of the JDO API for the persistence and portability requirements of complex biological databasesExample of JDO file. This file is used to define the persistent classes that are used in SigPath to represent end-users. Four persistent classes are shown: Address, Affiliation, User and UserRole. The <field> element can be used to refer to specific fields of persistent classes (such as the username field of class User on this example). The userRoles field is described to be a collection that contains elements of type UserRole. Elements called <extension> make it possible to provide vendor specific directives, such as to define indices on a persistent field.Back to article page