Top Description Methods
javax.persistence

public @Interface MapKeyColumn

extends Annotation
Annotations
@Target:METHOD, FIELD
@Retention:RUNTIME
Imports
java.lang.annotation.Target, .Retention
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

Method Summary

Modifier and TypeMethod and Description
public String
columnDefinition()

(Optional) The SQL fragment that is used when generating the DDL for the column.

public boolean
insertable()

(Optional) Whether the column is included in SQL INSERT statements generated by the persistence provider.

public int
length()

(Optional) The column length.

public String
name()

(Optional) The name of the map key column.

public boolean
nullable()

(Optional) Whether the database column is nullable.

public int
precision()

(Optional) The precision for a decimal (exact numeric) column.

public int
scale()

(Optional) The scale for a decimal (exact numeric) column.

public String
table()

(Optional) The name of the table that contains the column.

public boolean
unique()

(Optional) Whether the column is a unique key.

public boolean
updatable()

(Optional) Whether the column is included in SQL UPDATE statements generated by the persistence provider.

Inherited from java.lang.annotation.Annotation:
annotationTypeequalshashCodetoString

Method Detail

columnDefinitionback to summary
public String columnDefinition()

(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.

insertableback to summary
public boolean insertable()

(Optional) Whether the column is included in SQL INSERT statements generated by the persistence provider.

lengthback to summary
public int length()

(Optional) The column length. (Applies only if a string-valued column is used.)

nameback to summary
public String name()

(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".

nullableback to summary
public boolean nullable()

(Optional) Whether the database column is nullable.

precisionback to summary
public int precision()

(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.)

scaleback to summary
public int scale()

(Optional) The scale for a decimal (exact numeric) column. (Applies only if a decimal column is used.)

tableback to summary
public String table()

(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.

uniqueback to summary
public boolean unique()

(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.

updatableback to summary
public boolean updatable()

(Optional) Whether the column is included in SQL UPDATE statements generated by the persistence provider.