EJB Relation Definition

Question

All,
My appoligies if this is a stupid question, but I have been reading up on this subject and I still do not quite understand what is needed and how to apply it to my specific situation.
What I have is a series of Oracle database views exposing data to our web service. We have chosen to use EJB's to expose that information to outside processes.
For this example I have two Database Views (Location and Citizen_Country) and two EJB's defined (Location and CitizenCountry). I want to have the CitizenCountry EJB invoke the Location EJB to pull up the country name and country code from the Location EJB for each record in the CitizenCountry EJB. The joining field in the views is COUNTRY_ID to GEO_LOC_ID.
If I was doing this in a standard SQL I would use a select * from Location l, CitizenCountry cc where l.geo_loc_id = cc.country_id;
I could also invoke both EJBs and combine the infromation before returing it.
What I want to be able to do is invoke the CitizenCountry EJB and have the NamedQuery inside it return all the records from CitizenCountry and the look-up data from Location as a single record. I would expect the Location information to be nested (ex. CitizenCountry.Location to get the location information).
Many thanks for any infromation to point me in the right direction.
Here are the definitions of the EJBs:
@Entity
@NamedQueries ({
@NamedQuery(name = "CitizenCountry.findAll",
query = "select o from CitizenCountry o"),
@NamedQuery(name = "CitizenCountry.findByAplId",
query = "select o from CitizenCountry o where o.aplId = :aplId_in")
@Table(name = "CITIZEN_COUNTRY")
public class CitizenCountry implements Serializable {
@Id
@Column(name="APL_ID", nullable = false)
private Long aplId;
@Column(name="COUNTRY_ID", nullable = false)
private Long countryId;
@Column(name="CS_DATE")
private Timestamp csDate;
@Column(name="CS_TO_DATE")
private Timestamp csToDate;
public CitizenCountry() {
@Entity
@NamedQueries ({
@NamedQuery(name = "Location.findAll", query = "select o from Location o"),
@NamedQuery(name = "Location.findAll", query = "select o from Location o where o.geoLocId = :in_GeoLocId")
@Table(name = "LOCATION")
public class Location implements Serializable {
@Column(name="CITY_CD")
private String cityCd;
@Column(name="CITY_CD_ALT")
private String cityCdAlt;
@Column(name="CITY_NM")
private String cityNm;
@Column(name="COUNTRY_CD")
private String countryCd;
@Column(name="COUNTRY_CD_ALT")
private String countryCdAlt;
@Column(name="COUNTRY_NM")
private String countryNm;
@Column(name="COUNTY_CD")
private String countyCd;
@Column(name="COUNTY_CD_ALT")
private String countyCdAlt;
@Column(name="COUNTY_NM")
private String countyNm;
@Id
@Column(name="GEO_LOC_ID", nullable = false)
private Long geoLocId;
@Column(name="STATE_CD")
private String stateCd;
@Column(name="STATE_CD_ALT")
private String stateCdAlt;
@Column(name="STATE_NM")
private String stateNm;
@Column(name="ZIP_CD")
private String zipCd;
public Location() {
}

Answer 1

Read about defining multiplicity in entity relationships here: http://download.oracle.com/javaee/6/tutorial/doc/bnbqa.html#bnbqh