Module jakarta.persistence
Package jakarta.persistence

Annotation Interface JoinColumns

@Target({METHOD,FIELD}) @Retention(RUNTIME) public @interface JoinColumns
Specifies the mapping for composite foreign keys. This annotation groups JoinColumn annotations for the same relationship.

Each JoinColumn annotation must explicit specify both name and referencedColumnName.

Since @JoinColumn is a repeatable annotation, it's not usually necessary to specify @JoinColumns explicitly: 

@ManyToOne
@JoinColumn(name = "ADDR_ID", referencedColumnName = "ID")
@JoinColumn(name = "ADDR_ZIP", referencedColumnName = "ZIP")
public Address getAddress() { return address; }

However, @JoinColumns is useful for controlling generation of composite foreign key constraints: 

@ManyToOne
@JoinColumns(
        value = {@JoinColumn(name = "ADDR_ID", referencedColumnName = "ID"),
                 @JoinColumn(name = "ADDR_ZIP", referencedColumnName = "ZIP")},
        foreignKey = @ForeignKey(name = "PERSON_ADDRESS_FK"))
public Address getAddress() { return address; }
Since:
1.0
See Also:

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    ForeignKey
    foreignKey
    (Optional) Controls generation of the foreign key constraint on these join columns when table generation is in effect.
    JoinColumn[]
    value
    (Optional) The join columns that map the relationship.

  • Element Details

    • value

      JoinColumn[] value
      (Optional) The join columns that map the relationship.

      If no @JoinColumns are specified, the join columns are inferred according to the relationship mapping defaults, exactly as if the @JoinColumns annotation was missing. This allows the foreignKey() to be specified when the join columns are defaulted.

      Default:
      {}

    • foreignKey

      ForeignKey foreignKey
      (Optional) Controls generation of the foreign key constraint on these join columns when table generation is in effect.
      • If both this element and a foreignKey element of one of the JoinColumn annotations are specified, the behavior is undefined.
      • If no ForeignKey annotation is specified in either location, a default foreign key strategy is selected by the persistence provider.
      Since:
      2.1
      See Also:
      Default:
      @jakarta.persistence.ForeignKey(PROVIDER_DEFAULT)