javax.persistence
Annotation Type OneToOne

@Target(value={METHOD,FIELD})
@Retention(value=RUNTIME)
public @interface OneToOne

This annotation defines a single-valued association to another entity that has one-to-one multiplicity. It is not normally necessary to specify the associated target entity explicitly since it can usually be inferred from the type of the object being referenced.

    Example 1: One-to-one association that maps a foreign key column
    On Customer class:




Since:
  
Java Persistence 1.0







Optional Element Summary




 CascadeType[]
cascade



          (Optional) The operations that must be cascaded to the target of the
 association.



 FetchType
fetch



          (Optional) Whether the association should be lazily loaded or must be
 eagerly fetched.



 java.lang.String
mappedBy



          (Optional) The field that owns the relationship.



 boolean
optional



          (Optional) Whether the association is optional.



 boolean
orphanRemoval



          (Optional) Whether to apply the remove operation to entities that have
 been removed from the relationship and to cascade the remove operation to
 those entities.



 java.lang.Class
targetEntity



          (Optional) The entity class that is the target of the association.


 


targetEntity
public abstract java.lang.Class targetEntity

(Optional) The entity class that is the target of the association.
 
 

 Defaults to the type of the field or property that stores the
 association.







Default:
void.class





cascade
public abstract CascadeType[] cascade

(Optional) The operations that must be cascaded to the target of the
 association.
 
 

 By default no operations are cascaded.







Default:
{}





fetch
public abstract FetchType fetch

(Optional) Whether the association should be lazily loaded or must be
 eagerly fetched. The EAGER strategy is a
 requirement on the persistence provider runtime that the associated
 entity must be eagerly fetched. The LAZY strategy
 is a hint to the persistence provider runtime.







Default:
javax.persistence.FetchType.EAGER





optional
public abstract boolean optional

(Optional) Whether the association is optional. If set to false then a
 non-null relationship must always exist.







Default:
true





mappedBy
public abstract java.lang.String mappedBy

(Optional) The field that owns the relationship. This element is only
 specified on the inverse (non-owning) side of the association.







Default:
""





orphanRemoval
public abstract boolean orphanRemoval

(Optional) Whether to apply the remove operation to entities that have
 been removed from the relationship and to cascade the remove operation to
 those entities.





Since:
  
Java Persistence API 2.0


Default:
false