一对一关系

@Entity
@Table(name="person_one")
public class Person {
 private Integer id;
 private String name;
 private IDCard idcard;
 
 @OneToOne(cascade={CascadeType.ALL},optional=false)
 @JoinColumn(name="idcard_id")
 public IDCard getIdcard() {
  return idcard;
 }

 public void setIdcard(IDCard idcard) {
  this.idcard = idcard;
 }

 @Id @GeneratedValue
 public Integer getId() {
  return id;
 }
 
 public void setId(Integer id) {
  this.id = id;
 }
 @Column(length=12,nullable=false)
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 

}

 


@Entity
@Table(name="idcard_one")
public class IDCard {
 private Integer id;
 private String cardno;
 private Person person;
 
 @OneToOne(cascade={CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REFRESH}
 ,mappedBy="idcard")
 public Person getPerson() {
  return person;
 }
 public void setPerson(Person person) {
  this.person = person;
 }
 @Id @GeneratedValue
 public Integer getId() {
  return id;
 }
 public void setId(Integer id) {
  this.id = id;
 }
 
 @Column(length=18,nullable=false)
 public String getCardno() {
  return cardno;
 }
 public void setCardno(String cardno) {
  this.cardno = cardno;
 }
 

}