Hibernate JPA @NotFound Example

@NotFound

The @NotFound annotation is used to specify the NotFoundAction strategy for when an element is not found in a given association.

NotFound
Action to do when an element is not found on a association.

The NotFoundAction defines two possibilities:

EXCEPTION
An exception is thrown when an element is not found (default and recommended).

IGNORE
Ignore the element when not found in the database.

@NotFound association mapping

When dealing with associations which are not enforced by a Foreign Key, it’s possible to bump into inconsistencies if the child record cannot reference a parent entity.

By default, Hibernate will complain whenever a child association references a non-existing parent record. However, you can configure this behavior so that Hibernate can ignore such an Exception and simply assign null as a parent object referenced.

To ignore non-existing parent entity references, even though not really recommended, it’s possible to use the annotation org.hibernate.annotation.NotFound annotation with a value of org.hibernate.annotations.NotFoundAction.IGNORE.

The @ManyToOne and @OneToOne associations that are annotated with @NotFound(action = NotFoundAction.IGNORE) are always fetched eagerly even if the fetch strategy is set to FetchType.LAZY.

Considering the following City and Person entity mappings:

Example : @NotFound mapping example

@Entity
@Table( name = "Person" )
public static class Person {

@Id
private Long id;

private String name;

private String cityName;

@ManyToOne
@NotFound ( action = NotFoundAction.IGNORE )
@JoinColumn(
name = "cityName",
referencedColumnName = "name",
insertable = false,
updatable = false
)
private City city;

//Getters and setters are omitted for brevity

}

@Entity
@Table( name = "City" )
public static class City implements Serializable {

@Id
@GeneratedValue
private Long id;

private String name;

//Getters and setters are omitted for brevity

}