@JoinTable

From CauchoWiki

The @JoinTable annotation specifies an association table used by a @ManyToMany or unidirectional @OneToMany relation.

[edit] Annotation Definition

 public @interface JoinTable {
     String name() default "";
     String catalog() default "";
     String schema() default "";
     JoinColumn []joinColumns() default{};
     JoinColumn []inverseJoinColumns() default {};
     UniqueConstraint[] uniqueConstraints() default {};
 }

attribute	description	default
name	the database table name	the @Entity name
catalog	the database catalog
schema	the database schema
joinColumns	the key columns used to join with the source @Table
inverseColumns	the key columns used to join with the target @Table
uniqueConstraints	constraint directives when creating the database

[edit] See Also

• @Entity the owning entity
• @ManyToMany many-to-many relation
• @OneToMany one-to-many relation
• @JoinColumn join (foreign) column configuration
• Relation catalog

[edit] Example: unidirectional @OneToMany with specified SQL

   @Entity
   @Table(name="s")
   public class Src {
       @Id 
       @Column(name="s_id")
       int getId() { ... }
 
       @OneToMany
       @JoinTable(name="map",
                  joinColumns={@JoinColumn(name="s_key")},
                  inverseJoinColumns={@JoinColumn(name="d_key")})
       Collection<Dst> getChildren() { ... }
   }

   @Entity
   @Table(name="d")
   public class Dst {
       @Id
       @Column(name="d_id")
       int getId() { ... }
    }

   create table s (
       s_id integer primary key
   )
   
   create table d (
       d_id integer primary key
   )

   create table map (
       s_key integer references(s, s_id),

       d_key integer references(d, d_id)
   )