I don't know what exactly you mean with "without mapping that to the database", but anyway I have solved something similar as follows: | @Entity | @Table(name = "person", uniqueConstraints = @UniqueConstraint(columnNames = {"firstname", "lastname"})) | public class Person { | @Id | private Long id; | @Column(name = "firstname") | private String firstName; | @Column(name = "lastname") | private String lastName; | private String address; | | public Long getId() { | return id; | } | | public void setId(Long id) { | this.id = id; | } | | public String getFirstName() { | return firstName; | } | | public void setFirstName(String firstName) { | this.firstName = firstName; | } | | public String getLastName() { | return lastName; | } | | public void setLastName(String lastName) { | this.lastName = lastName; | } | | public String getAddress() { | return address; | } | | public void setAddress(String address) { | this.address = address; | } | } | | With above, the validation is done in database layer, but it is caught by JPA and it throws a javax.persistence.EntityExistsException. It works for me in the sense I don't have to write any special login in a Session Bean to validate this. HTH. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4048884#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...