Latest revision as of 14:00, 27 October 2011

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Key API

• @Enumerated
• EnumType

Examples

• Map Enum to Coded Values

@Enumerated

By default, EclipseLink persistence provider persists the ordinal values of enumerated constants.

Use the @Enumerated annotation to specify whether EclipseLink persistence provider should persist ordinal (integer) or String values of enumerated constants if the String value suits your application requirements, or to match an existing database schema:

You can use this annotation with the @Basic annotation.

Given the enumerated constants in the Enumerated Constants example, the @Enumerated Annotation example, below, shows how to use the @Enumerated annotation to specify that the String value of SalaryRate should be written to the database when Employee is persisted. By default, the ordinal value of EmployeeStatus is written to the database.

Example: Enumerated Constants

public enum EmployeeStatus {FULL_TIME, PART_TIME, CONTRACT}
public enum SalaryRate {JUNIOR, SENIOR, MANAGER, EXECUTIVE}

Example: @Enumerated Annotation

@Entity
public class Employee implements Serializable{
    ...
    public EmployeeStatus getStatus() {
        ...
    }
 
    @Enumerated(STRING)
    public SalaryRate getRate() {
        ...
    }
    ...
}

Example: Using <enumerated> XML

<entity class="Employee">
    <attributes>
        ...
        <basic name="status"/>
        <basic name="rate">
            <enumerated>STRING</enumerated>
        </basic>
        ...
    </attributes>
</entity>

For more information, see Section 9.1.21 "Enumerated Annotation" in the JPA Specification.

Legacy Data

Another option for mapping enumerated values is to use an ObjectTypeConverter. A converter allows for type codes to be used on the database instead of the enum's name, which may be required for legacy data.

See, ObjectTypeConverter

@Basic	Basic Mappings	@Temporal
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