Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
This program and the accompanying materials are made available under the
terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
which accompanies this distribution.
The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
http://www.eclipse.org/org/documents/edl-v10.php.
Contributors:
Linda DeMichiel - Java Persistence 2.1
Linda DeMichiel - Java Persistence 2.0
/*******************************************************************************
* Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Linda DeMichiel - Java Persistence 2.1
* Linda DeMichiel - Java Persistence 2.0
*
******************************************************************************/
package javax.persistence;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
Specifies the mapping for the key column of a map whose
map key is a basic type. If the name element is not specified, it
defaults to the concatenation of the following: the name of the
referencing relationship field or property; "_"; "KEY".
Example:
@Entity
public class Item {
@Id int id;
...
@ElementCollection
@MapKeyColumn(name="IMAGE_NAME")
@Column(name="IMAGE_FILENAME")
@CollectionTable(name="IMAGE_MAPPING")
Map<String, String> images; // map from image name to filename
...
}
Since: Java Persistence 2.0
/**
* Specifies the mapping for the key column of a map whose
* map key is a basic type. If the <code>name</code> element is not specified, it
* defaults to the concatenation of the following: the name of the
* referencing relationship field or property; "_"; "KEY".
*
* <pre>
* Example:
*
* @Entity
* public class Item {
* @Id int id;
* ...
* @ElementCollection
* @MapKeyColumn(name="IMAGE_NAME")
* @Column(name="IMAGE_FILENAME")
* @CollectionTable(name="IMAGE_MAPPING")
* Map<String, String> images; // map from image name to filename
* ...
* }
* </pre>
* @since Java Persistence 2.0
*/
@Target( { METHOD, FIELD })
@Retention(RUNTIME)
public @interface MapKeyColumn {
(Optional) The name of the map key column. The table in which it is found
depends upon the context. If the map key is for an element collection,
the map key column is in the collection table for the map value. If the
map key is for a ManyToMany entity relationship or for a OneToMany entity
relationship using a join table, the map key column is in a join table.
If the map key is for a OneToMany entity relationship using a foreign key
mapping strategy, the map key column is in the table of the entity that
is the value of the map.
Defaults to the concatenation of the following: the name of
the referencing relationship field or property; "_"; "KEY".
/**
* (Optional) The name of the map key column. The table in which it is found
* depends upon the context. If the map key is for an element collection,
* the map key column is in the collection table for the map value. If the
* map key is for a ManyToMany entity relationship or for a OneToMany entity
* relationship using a join table, the map key column is in a join table.
* If the map key is for a OneToMany entity relationship using a foreign key
* mapping strategy, the map key column is in the table of the entity that
* is the value of the map.
* <p> Defaults to the concatenation of the following: the name of
* the referencing relationship field or property; "_"; "<code>KEY</code>".
*/
String name() default "";
(Optional) Whether the column is a unique key. This is a
shortcut for the UniqueConstraint annotation
at the table level and is useful for when the unique key
constraint corresponds to only a single column. This
constraint applies in addition to any constraint entailed
by primary key mapping and to constraints specified at the
table level.
/**
* (Optional) Whether the column is a unique key. This is a
* shortcut for the <code>UniqueConstraint</code> annotation
* at the table level and is useful for when the unique key
* constraint corresponds to only a single column. This
* constraint applies in addition to any constraint entailed
* by primary key mapping and to constraints specified at the
* table level.
*/
boolean unique() default false;
(Optional) Whether the database column is nullable. /** (Optional) Whether the database column is nullable. */
boolean nullable() default false;
(Optional) Whether the column is included in SQL INSERT statements
generated by the persistence provider.
/**
* (Optional) Whether the column is included in SQL INSERT statements
* generated by the persistence provider.
*/
boolean insertable() default true;
(Optional) Whether the column is included in SQL UPDATE statements
generated by the persistence provider.
/**
* (Optional) Whether the column is included in SQL UPDATE statements
* generated by the persistence provider.
*/
boolean updatable() default true;
(Optional) The SQL fragment that is used when generating the DDL for the
column.
Defaults to the generated SQL to create a
column of the inferred type.
/**
* (Optional) The SQL fragment that is used when generating the DDL for the
* column.
* <p> Defaults to the generated SQL to create a
* column of the inferred type.
*
*/
String columnDefinition() default "";
(Optional) The name of the table that contains the column.
Defaults: If the map key is for an element collection,
the name of the collection table for the map value. If the
map key is for a OneToMany or ManyToMany entity
relationship using a join table, the name of the join table
for the map. If the map key is for a OneToMany entity
relationship using a foreign key mapping strategy, the name
of the primary table of the entity that is the value of the
map.
/** (Optional) The name of the table that contains the column.
*
* <p> Defaults: If the map key is for an element collection,
* the name of the collection table for the map value. If the
* map key is for a OneToMany or ManyToMany entity
* relationship using a join table, the name of the join table
* for the map. If the map key is for a OneToMany entity
* relationship using a foreign key mapping strategy, the name
* of the primary table of the entity that is the value of the
* map.
*/
String table() default "";
(Optional) The column length. (Applies only if a string-valued column is
used.)
/**
* (Optional) The column length. (Applies only if a string-valued column is
* used.)
*/
int length() default 255;
(Optional) The precision for a decimal (exact numeric) column. (Applies
only if a decimal column is used.)
Default: 0. (The value must be set by the developer.)
/**
* (Optional) The precision for a decimal (exact numeric) column. (Applies
* only if a decimal column is used.)
*
*<p> Default: 0. (The value must be set by the developer.)
*/
int precision() default 0; // decimal precision
(Optional) The scale for a decimal (exact numeric) column. (Applies only
if a decimal column is used.)
/**
* (Optional) The scale for a decimal (exact numeric) column. (Applies only
* if a decimal column is used.)
*/
int scale() default 0; // decimal scale
}