I'm trying to define a one-to-one bidirectional relationship in which one row may or may not exist. I thought setting optional=true (on both sides?) would allow for this but I get the following error:

Caused by: org.hibernate.ObjectNotFoundException: No row with the given identifier exists: [com.xxx.entity.UserAlertsProfile#425195]

@Entity
@Name("userRecord")
@Table(name = "RHTCONTACT")
@Scope(ScopeType.SESSION)
public class UserRecord implements IUserRecord, java.io.Serializable {

 /**
 * Retrieves the ContactKey from the entity
 */
 @Id
 @Length(max = 22)
 @Column(name = "CONTACT_KEY", length = 22, nullable = false)
 public Long getContactKey() {
 return this.contactKey;
 }

 /**
 * Sets the ContactKey of the entity
 */
 public void setContactKey(Long contactKey) {
 this.contactKey = contactKey;
 }

 /**
 * @return the alertsProfile
 */
 @OneToOne(optional=true, fetch=FetchType.EAGER)
 @JoinColumn(name="USER_KEY", unique=true, nullable=false, updatable=false, insertable=false)
 public UserAlertsProfile getAlertsProfile() {
 return alertsProfile;
 }

 /**
 * @param alertsProfile the alertsProfile to set
 */
 public void setAlertsProfile(UserAlertsProfile alertsProfile) {
 this.alertsProfile = alertsProfile;
 }
 ...
}

@Entity
@Name("alertsprofile")
@Table(name = "USER_PROFILE_ALERTS")
public class UserAlertsProfile implements java.io.Serializable {

 /**
 * Retrieves the UserKey from the entity
 */
 @Id
 @Length(max = 22)
 @Column(name = "USER_KEY", length = 22, nullable = false)
 public Long getUserKey() {
 return this.userKey;
 }

 /**
 * Sets the UserKey of the entity
 */
 public void setUserKey(Long userKey) {
 this.userKey = userKey;
 }

 /**
 * @return the userRecord
 */
 @OneToOne(optional=true, mappedBy="accountInfo")
 public UserRecord getUserRecord() {
 return userRecord;
 }

 /**
 * @param userRecord the userRecord to set
 */
 public void setUserRecord(UserRecord userRecord) {
 this.userRecord = userRecord;
 }
}