Package org.hibernate.annotations

Annotation Interface Any

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface Any

Maps a to-one cardinality association taking values over several entity types which are not related by the usual entity inheritance, using a discriminator value stored on the referring side of the relationship.

This is quite different to discriminated inheritance where the discriminator is stored along with the referenced entity hierarchy.

For example, consider an Order entity containing Payment information, where a Payment might be a CashPayment or a CreditCardPayment. An @Any mapping would store the discriminator value identifying the concrete type of Payment along with the state of the associated Order, instead of storing it with the Payment entity itself.

 interface Payment { ... }

 @Entity
 class CashPayment { ... }

 @Entity
 class CreditCardPayment { ... }

 @Entity
 class Order {
     ...
     @Any
     @AnyKeyJavaClass(UUID.class)   //the foreign key type
     @JoinColumn(name="payment_id") //the foreign key column
     @Column(name="payment_type")   //the discriminator column
     @AnyDiscriminatorValue(discriminator="CASH", entity=CashPayment.class)
     @AnyDiscriminatorValue(discriminator="CREDIT", entity=CreditCardPayment.class)
     Payment payment;
     ...
 }
 

In this example, Payment is not be declared as an entity type, and is not annotated @Entity. It might even be an interface, or at most just a mapped superclass, of CashPayment and CreditCardPayment. So in terms of the object/relational mappings, CashPayment and CreditCardPayment would not be considered to participate in the same entity inheritance hierarchy. On the other hand, CashPayment and CreditCardPayment must have the same identifier type.

It's reasonable to think of the "foreign key" in an Any mapping is really a composite value made up of the foreign key and discriminator taken together. Note, however, that this composite foreign key is only conceptual and cannot be declared as a physical constraint on the relational database table.

• AnyDiscriminator, JdbcType, or JdbcTypeCode specifies the type of the discriminator.
• AnyDiscriminatorValue specifies how discriminator values map to entity types.
• Column or Formula specifies the column or formula in which the discriminator value is stored.
• AnyKeyJavaType, AnyKeyJavaClass, AnyKeyJdbcType, or AnyKeyJdbcTypeCode specifies the type of the foreign key.
• JoinColumn specifies the foreign key column.

Of course, Any mappings are disfavored, except in extremely special cases, since it's much more difficult to enforce referential integrity at the database level.

See Also:

• ManyToAny

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
FetchType	fetch	Specifies whether the value of the field or property may be lazily loaded or must be eagerly fetched: EAGER specifies that the association must be eagerly fetched.
boolean	optional	Whether the association is optional.

Element Details

fetch

FetchType fetch

Specifies whether the value of the field or property may be lazily loaded or must be eagerly fetched:

• EAGER specifies that the association must be eagerly fetched.
• LAZY allows the association to be fetched lazily, but this is possible only when bytecode enhancement is used.

If not explicitly specified, the default is EAGER.

Default:

EAGER

optional

boolean optional

Whether the association is optional.

If the discriminator Column or the JoinColumn are not nullable the association is always considered non-optional, regardless of this value.

Returns:

false if the association cannot be null.

Default:

true