@Target(value={METHOD,FIELD}) @Retention(value=RUNTIME) public @interface MapKeyJoinColumn
MapKeyJoinColumn
annotation is specified, a single
join column is assumed and the default values apply.
Example 1: @Entity public class Company { @Id int id; ... @OneToMany // unidirectional @JoinTable(name="COMPANY_ORGANIZATION", joinColumns=@JoinColumn(name="COMPANY"), inverseJoinColumns=@JoinColumn(name="VICEPRESIDENT")) @MapKeyJoinColumn(name="DIVISION") Map<Division, VicePresident> organization; } Example 2: @Entity public class VideoStore { @Id int id; String name; Address location; ... @ElementCollection @CollectionTable(name="INVENTORY", joinColumns=@JoinColumn(name="STORE")) @Column(name="COPIES_IN_STOCK") @MapKeyJoinColumn(name="MOVIE", referencedColumnName="ID") Map<Movie, Integer> videoInventory; ... } @Entity public class Movie { @Id long id; String title; ... } Example 3: @Entity public class Student { @Id int studentId; ... @ManyToMany // students and courses are also many-many @JoinTable(name="ENROLLMENTS", joinColumns=@JoinColumn(name="STUDENT"), inverseJoinColumns=@JoinColumn(name="SEMESTER")) @MapKeyJoinColumn(name="COURSE") Map<Course, Semester> enrollment; ... }
Modifier and Type | Optional Element and Description |
---|---|
String |
columnDefinition
(Optional) The SQL fragment that is used when generating the DDL for the
column.
|
boolean |
insertable
(Optional) Whether the column is included in SQL INSERT statements
generated by the persistence provider.
|
String |
name
(Optional) The name of the foreign key column for the map
key.
|
boolean |
nullable
(Optional) Whether the foreign key column is nullable.
|
String |
referencedColumnName
(Optional) The name of the column referenced by this foreign key column.
|
String |
table
(Optional) The name of the table that contains the foreign key column.
|
boolean |
unique
(Optional) Whether the property is a unique key.
|
boolean |
updatable
(Optional) Whether the column is included in SQL UPDATE statements
generated by the persistence provider.
|
public abstract String name
Default (only applies if a single join column is used.) The concatenation of the following: the name of the referencing relationship property or field of the referencing entity or embeddable class; "_"; "KEY".
public abstract String referencedColumnName
Default (only applies if single join column is being used.) The same name as the primary key column of the referenced table
public abstract boolean unique
UniqueConstraint
annotation
at the table level and is useful for when the unique key
constraint is only a single field.public abstract boolean nullable
public abstract boolean insertable
public abstract boolean updatable
public abstract String columnDefinition
public abstract String table
Default:
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