Annotation Interface OneToOne
mappedBy
element of
the OneToOne
annotation to specify the relationship field or
property of the owning side.
The OneToOne
annotation may be used within an
embeddable class to specify a relationship from the embeddable
class to an entity class. If the relationship is bidirectional and
the entity containing the embeddable class is on the owning side of
the relationship, the non-owning side must use the
mappedBy
element of the OneToOne
annotation to specify the relationship field or property of the
embeddable class. The dot (".") notation syntax must be used in the
mappedBy
element to indicate the relationship attribute within the
embedded attribute. The value of each identifier used with the dot
notation is the name of the respective embedded field or property.
Example 1: One-to-one association that maps a foreign key column // On Customer class: @OneToOne(optional=false) @JoinColumn( name="CUSTREC_ID", unique=true, nullable=false, updatable=false) public CustomerRecord getCustomerRecord() { return customerRecord; } // On CustomerRecord class: @OneToOne(optional=false, mappedBy="customerRecord") public Customer getCustomer() { return customer; } Example 2: One-to-one association that assumes both the source and target share the same primary key values. // On Employee class: @Entity public class Employee { @Id Integer id; @OneToOne @MapsId EmployeeInfo info; ... } // On EmployeeInfo class: @Entity public class EmployeeInfo { @Id Integer id; ... } Example 3: One-to-one association from an embeddable class to another entity. @Entity public class Employee { @Id int id; @Embedded LocationDetails location; ... } @Embeddable public class LocationDetails { int officeNumber; @OneToOne ParkingSpot parkingSpot; ... } @Entity public class ParkingSpot { @Id int id; String garage; @OneToOne(mappedBy="location.parkingSpot") Employee assignedTo; ... }
- Since:
- 1.0
-
Optional Element Summary
Modifier and TypeOptional ElementDescription(Optional) The operations that must be cascaded to the target of the association.(Optional) Whether the association should be lazily loaded or must be eagerly fetched.(Optional) The field that owns the relationship.boolean
(Optional) Whether the association is optional.boolean
(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.(Optional) The entity class that is the target of the association.
-
Element Details
-
targetEntity
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
CascadeType[] cascade(Optional) The operations that must be cascaded to the target of the association.By default no operations are cascaded.
- Default:
- {}
-
fetch
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:
- EAGER
-
optional
boolean optional(Optional) Whether the association is optional. If set to false then a non-null relationship must always exist.- Default:
- true
-
mappedBy
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
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:
- 2.0
- Default:
- false
-