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Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Entities/Ids/Generating and Configuring Entity Identities"
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Every entity must have a persistent identity, which is an equivalent of a primary key in a database table that stores the entity state. | Every entity must have a persistent identity, which is an equivalent of a primary key in a database table that stores the entity state. | ||
| − | By default, the [[EclipseLink/UserGuide/JPA/Basic JPA Development/persistence.xml|EclipseLink persistence provider]] assumes that each entity has at least one field or property that serves as a primary key. | + | By default, the [[EclipseLink/UserGuide/JPA/Basic JPA Development/Configuration/JPA/persistence.xml|EclipseLink persistence provider]] assumes that each entity has at least one field or property that serves as a primary key. |
You can generate and/or configure the identity of your entities by using the following annotations: | You can generate and/or configure the identity of your entities by using the following annotations: | ||
Revision as of 12:22, 15 June 2010
Entity
Every entity must have a persistent identity, which is an equivalent of a primary key in a database table that stores the entity state.
By default, the EclipseLink persistence provider assumes that each entity has at least one field or property that serves as a primary key.
You can generate and/or configure the identity of your entities by using the following annotations:
- @Id
- @IdClass
- @EmbeddedId
- @GeneratedValue
- @TableGenerator
- @SequenceGenerator
You can also use these annotations to fine-tune how your database maintains the identity of your entities.
 Mapping |
@Id |
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