Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Mapping/Basic Mappings/Transient"

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(@Transient)
(Example: @Transient Annotation)
 
Line 30: Line 30:
 
@Entity
 
@Entity
 
public class Employee implements Serializable {
 
public class Employee implements Serializable {
    ...
 
 
     @Id
 
     @Id
 
     int id;
 
     int id;
Line 38: Line 37:
 
     ...
 
     ...
 
}
 
}
 +
</source>
 +
 +
======''Example: Using <code><nowiki><transient></nowiki></code> XML''======
 +
<source lang="xml">
 +
<entity class="Employee">
 +
    <attributes>
 +
        <id name="id"/>
 +
        <transient name="currentSession"/>
 +
        ...
 +
    </attributes>
 +
</entity>
 
</source>
 
</source>
  

Latest revision as of 15:16, 27 October 2011

EclipseLink JPA

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[edit] @Transient

By default, EclipseLink persistence provider assumes that all the fields of an entity are persistent.

Use the @Transient annotation or <transient> XML to specify a field or property of an entity that is not persistent (for example, a field or property that is used at run time, but that is not part of the entity's state).

EclipseLink persistence provider will not persist (or create database schema) for a property or field annotated with @Transient.

This annotation can be used with @Entity, @MappedSuperclass, and @Embeddable.

Elug javaspec icon.gif

For more information, see Section 8.1 "Entity" in the JPA Specification.

The @Transient annotation does not have attributes.

If a field is marked as Java transient it will also be ignored.

The following example shows how to use the @Transient annotation to specify Employee field currentSession as not persistent. EclipseLink persistence provider will not persist this field.

[edit] Example: @Transient Annotation
@Entity
public class Employee implements Serializable {
    @Id
    int id;
 
    @Transient
    Session currentSession;
    ...
}
[edit] Example: Using <transient> XML
<entity class="Employee">
    <attributes>
        <id name="id"/>
        <transient name="currentSession"/>
        ...
    </attributes>
</entity>
Elug javaspec icon.gif

For more information, see Section 11.1.48 "Transient Annotation" in the JPA Specification.


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