Note: This ORM/SQL annotation is silently ignored by ObjectDB

942 words

javax.persistence.AttributeOverride - JPA annotation

javax.persistence
Annotation AttributeOverride

Target:
Classes and fields (including property get methods)
Used to override the mapping of a Basic (whether explicit or default) property or field or Id property or field.

May be applied to an entity that extends a mapped superclass or to an embedded field or property to override a basic mapping or id mapping defined by the mapped superclass or embeddable class (or embeddable class of one of its attributes).

May be applied to an element collection containing instances of an embeddable class or to a map collection whose key and/or value is an embeddable class. When AttributeOverride is applied to a map, "key." or "value." must be used to prefix the name of the attribute that is being overridden by order to specify it as part of the map key or map value.

To override mappings at multiple levels of embedding, a dot (".") notation form must be used in the name element to indicate an attribute within an embedded attribute. The value of each identifier used with the dot notation is the name of the respective embedded field or property.

If AttributeOverride is not specified, the column is mapped the same as in the original mapping.

Example 1:

    @MappedSuperclass
    public class Employee {
        @Id protected Integer id;
        @Version protected Integer version;
        protected String address;
        public Integer getId() { ... }
        public void setId(Integer id) { ... }
        public String getAddress() { ... }
        public void setAddress(String address) { ... }
    }
 
    @Entity
    @AttributeOverride(name="address", column=@Column(name="ADDR"))
    public class PartTimeEmployee extends Employee {
        // address field mapping overridden to ADDR
        protected Float wage();
        public Float getHourlyWage() { ... }
        public void setHourlyWage(Float wage) { ... }
    }

Example 2:

    @Embeddable public class Address {
        protected String street;
        protected String city;
        protected String state;
        @Embedded protected Zipcode zipcode;
    }
 
    @Embeddable public class Zipcode {
        protected String zip;
        protected String plusFour;
    }
 
    @Entity public class Customer {
        @Id protected Integer id;
        protected String name;
        @AttributeOverrides({
            @AttributeOverride(name="state",
                               column=@Column(name="ADDR_STATE")),
            @AttributeOverride(name="zipcode.zip",
                               column=@Column(name="ADDR_ZIP"))
        })
        @Embedded protected Address address;
        ...
    }

Example 3:

    @Entity public class PropertyRecord {
        @EmbeddedId PropertyOwner owner;
        @AttributeOverrides({
            @AttributeOverride(name="key.street", 
                               column=@Column(name="STREET_NAME")),
            @AttributeOverride(name="value.size", 
                               column=@Column(name="SQUARE_FEET")),
            @AttributeOverride(name="value.tax", 
                               column=@Column(name="ASSESSMENT"))
        })
       @ElementCollection
       Map<Address, PropertyInfo> parcels;
    }
 
   @Embeddable public class PropertyInfo {
       Integer parcelNumber;
       Integer size;
       BigDecimal tax;
   }

Since:
JPA 1.0
See Also:
Embedded
Embeddable
MappedSuperclass
AssociationOverride
(Required) The column that is being mapped to the persistent attribute.
(Required) The column that is being mapped to the persistent attribute. The mapping type will remain the same as is defined in the embeddable class or mapped superclass.
Since:
JPA 1.0
String name
(Required) The name of the property whose mapping is being overridden if property-based access is being used, or the name of the field if field-based access is used.
(Required) The name of the property whose mapping is being overridden if property-based access is being used, or the name of the field if field-based access is used.
Since:
JPA 1.0

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.