Changing the generated name of a foreign key in Hibernate

Question

@OneToOne() @JoinColumn(name="vehicle_id", referencedColumnName="vehicleId") public Vehicle getVehicle() {     return vehicle; } 

My UserDetails class has a one-to-one mapping with the Entitity class Vehicle. Hibernate creates the 2 tables and assigns a generic Foreign Key, which maps the vehicle_id column (UserDetails table.) to the primary key vehicleId (Vehicle table).

KEY FKB7C889CEAF42C7A1 (vehicle_id), CONSTRAINT FKB7C889CEAF42C7A1 FOREIGN KEY (vehicle_id) REFERENCES vehicle (vehicleId) 

My question is : how do we change this generated foreign key, into something meaningful, like Fk_userdetails_vehicle for example.

Answer 1

Since JPA 2.1, you can use the @javax.persistence.ForeignKey annotation:

@OneToOne() @JoinColumn(name="vehicle_id", referencedColumnName="vehicleId", foreignKey=@ForeignKey(name = "Fk_userdetails_vehicle")) public Vehicle getVehicle() {     return vehicle; } 

Prior to JPA 2.1, you could use Hibernate’s @org.hibernate.annotations.ForeignKey annotation, but this is now deprecated:

@OneToOne() @JoinColumn(name="vehicle_id", referencedColumnName="vehicleId") @ForeignKey(name="Fk_userdetails_vehicle") public Vehicle getVehicle() {    return vehicle; } 

Answer 2

Also you can use @ForeignKey embedded in @JoinColumn like this:

@JoinColumn(name = "BAR_ID", foreignKey = @ForeignKey(name = FK_BAR_OF_FOO)) 

for @ManyToMany relations you can use foreignKey and inverseForeignKey embedded in @JoinTable like this:

@JoinTable(name = "ARC_EMPLOYEE_OF_BAR"         , joinColumns = {@JoinColumn(name = "BAR_ID")}         , inverseJoinColumns = {@JoinColumn(name = "EMPLOYEE_ID")}         , uniqueConstraints = {@UniqueConstraint(name = "ARC_UK_EMPLOYEE_OF_BAR", columnNames = {"EMPLOYEE_ID", "BAR_ID"})}         , foreignKey = @ForeignKey(name = "ARC_FK_BAR_OF_EMPLOYEE")         , inverseForeignKey = @ForeignKey(name = "ARC_FK_EMPLOYEE_OF_BAR"))