SELECT a.nusernr as userId, a.suserid as username, b.ssexid as gender, date_part( 'year', age( b.dbirth)) as age, c.bpicture as bpicture,d.ncountrynr as ncountrynr ,d.stld as stld ,d.siso as siso ,d.bflag as bflag ,d.scountry as scountry  FROM core_usge."user" a JOIN core_usda.person b ON (a.nusernr =? and b.nusernr = a.nusernr) JOIN community.userdata c ON (c.nusernr = a.nusernr) JOIN core_geo.country d ON (d.ncountrynr = c.ncountrynr) limit ?

Hibernate: select country0_.ncountrynr as ncountrynr0_0_, country0_.siso as siso0_0_, country0_.stld as stld0_0_, country0_.bflag as bflag0_0_, country0_.scountry as scountry0_0_ from core_geo.country country0_ where country0_.scountry=? and country0_.ncountrynr=?

@SqlResultSetMappings(
      value = {
            @SqlResultSetMapping(name = "UserStringMapping",
                  entities = {
                        @EntityResult(entityClass = UserString.class,

                              fields = {
                                    @FieldResult(name = "userId", column = "userId")
                                    , @FieldResult(name = "username", column = "username")
                                    , @FieldResult(name = "gender", column = "gender")
                                    , @FieldResult(name = "age", column = "age")

                                    , @FieldResult(name = "country.name", column = "scountry")
                                    , @FieldResult(name = "country.countryId", column = "ncountrynr")
                                    , @FieldResult(name = "country.TLD", column = "stld")
                                    , @FieldResult(name = "country.ISO", column = "siso")
                                    , @FieldResult(name = "country.flag", column = "bflag")
                              })
                  }
            )

      }
)
@Entity
public class UserString {


   private int userId = 0;
   private String username = "";
   private int age = 0;
   private boolean online = false;
   private Gender gender = null;

   private Country country;


   public UserString() {
   }

   @Id
   @Column(insertable = false, updatable = false)
   public int getUserId() {
      return userId;
   }

   public void setUserId(int userId) {
      this.userId = userId;
   }

   @Column(insertable = false, updatable = false)
   public String getUsername() {
      return username;
   }

   public void setUsername(String username) {
      this.username = username;
   }

   @Column(insertable = false, updatable = false)
   public int getAge() {
      return age;
   }

   public void setAge(int age) {
      this.age = age;
   }

   @Transient
   public boolean isOnline() {
      return online;
   }

   public void setOnline(boolean online) {
      this.online = online;
   }


   @Enumerated(EnumType.STRING)
   @Column(insertable = false, updatable = false)
   public Gender getGender() {
      return gender;
   }

   public void setGender(Gender gender) {
      this.gender = gender;
   }


   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumns(
         {
               @JoinColumn(name = "scountry", referencedColumnName = "scountry"),
               @JoinColumn(name = "ncountrynr", referencedColumnName = "ncountrynr")
         }
   )
   public Country getCountry() {
      return country;
   }

   public void setCountry(Country country) {
      this.country = country;
   }

   @Override
   public String toString() {
      return "UserString{" +
            "userId=" + userId +
            ", username='" + username + '\'' +
            ", age=" + age +
            ", online=" + online +
            ", gender=" + gender +
            ", country=" + country +
            '}';


   }
}

Caused by: org.hibernate.MappingException: dotted notation reference neither a component nor a many/one to one