Multiple unique constraints in JPA

Question

Is there a way to specify using JPA that there should be multiple unique constraints on different sets of columns?

@Entity @Table(name="person",         uniqueConstraints=@UniqueConstraint(columnNames={"code", "uid"})) public class Person {     // Unique on code and uid     public String code;     public String uid;      // Unique on username     public String username;      public String name;     public String email; } 

I have seen a hibernate specific annotation but I am trying to avoid vendor specific solutions as we are still deciding between hibernate and datanucleus.

Answer 1

The @Table's attribute uniqueConstraints actually accepts an array of these. Your example is just a shorthand for an array with a single element. Otherewise it would look like:

@Table(name="person",  uniqueConstraints={    @UniqueConstraint(columnNames={"code", "uid"}),    @UniqueConstraint(columnNames={"anotherField", "uid"}) }) 

Whenever the unique constraint is based only on one field, you can use @Column(unique=true) on that column.