We know that in hibernate the definition of a unique key is done
through the @UniqueConstraint annotation.
Within this annotation, placed on the class, you can specify the
fields that constitute the unique key :
@Entity
@Table(uniqueConstraints = { @UniqueConstraint(columnNames = "username"),
@UniqueConstraint(columnNames = "email") })
...
public class HUser extends HyperIoTAbstractEntity implements HyperIoTProtectedEntity, HyperIoTUser {
...
}
the Framework exploits this annotation to create at runtime checks
for uniqueness (by running dynamic queries) so as to perform a check
for existence of duplicates before the entity itself is saved to the
database. This allows for timely and automatic error handling that, in
case of duplicates, will report the detail of the field that generated
the “Duplicate Entity” error. In addition, this type of error is
automatically converted into a JSON response (for any REST services)
reporting the above details. Again , taking full advantage of all the
technologies involved and inserting a simple annotation the framework
will handle everything independently without having to add additional
code, but simply annotating the source entity.
