hibernate one to many
1.Unidirectionalwithjointable
参考例子
http://www.vaannila.com/hibernate/hibernate-example/hibernate-mapping-one-to-many-using-annotations-1.html
2.Unidirectionalwithforeignkey
PERSON
PERSON_ID
PERSON_NAME
ADDRESS
ADDRESS_ID
ADDRESS_NAME
P_ID
P_ID字段在ADDRESS表中，但其定义在PERSONentity中
@Entity
@Table(name = "PERSON")
public class Person {
private Integer id;
private String name;
private Set<Address> addressSet = new HashSet<Address>(0);
public Person() {
}
public Person(String name, Set<Address> addSet) {
this.name = name;
this.addressSet = addSet;
}
@Id
@GeneratedValue
@Column(name = "PERSON_ID")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(name = "PERSON_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinColumn(name = "P_ID")
public Set<Address> getAddressSet() {
return addressSet;
}
public void setAddressSet(Set<Address> addressSet) {
this.addressSet = addressSet;
}
@Override
public String toString() {
return this.id + "\t" + this.name;
}
}@Entity
@Table(name = "ADDRESS")
public class Address {
private Integer addressId;
private String name;
public Address()
{
}
public Address(String name)
{
this.name = name;
}
@Id
@GeneratedValue
@Column(name = "ADDRESS_ID")
public Integer getAddressId() {
return addressId;
}
public void setAddressId(Integer addressId) {
this.addressId = addressId;
}
@Column(name = "ADDRESS_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return this.addressId + "\t" + this.name;
}
}插入数据时，hibernate会生成如下sql
Hibernate:insertintoPERSON(PERSON_ID,PERSON_NAME)values(null,?)
Hibernate:insertintoADDRESS(ADDRESS_ID,ADDRESS_NAME)values(null,?)
Hibernate:insertintoADDRESS(ADDRESS_ID,ADDRESS_NAME)values(null,?)
Hibernate:updateADDRESSsetP_ID=?whereADDRESS_ID=?
Hibernate:updateADDRESSsetP_ID=?whereADDRESS_ID=?
hibernatedoc不建议使用此中连接，参考
http://docs.jboss.org/ejb3/app-server/HibernateAnnotations/reference/en/html_single/index.html#d0e1517
3.bidirectional
表结构
PERSON
PERSON_ID
PERSON_NAME
ADDRESS
ADDRESS_ID
ADDRESS_NAME
P_ID
A.manytoone端是owner
@Entity
@Table(name = "PERSON")
public class Person {
private Integer id;
private String name;
private Set<Address> addressSet = new HashSet<Address>(0);
public Person() {
}
public Person(String name, Set<Address> addSet) {
this.name = name;
this.addressSet = addSet;
}
@Id
@GeneratedValue
@Column(name = "PERSON_ID")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(name = "PERSON_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, [color=red]mappedBy = "person"[/color])
public Set<Address> getAddressSet() {
return addressSet;
}
public void setAddressSet(Set<Address> addressSet) {
this.addressSet = addressSet;
}
@Override
public String toString() {
return this.id + "\t" + this.name;
}
}@Entity
@Table(name = "ADDRESS")
public class Address {
private Integer addressId;
private String name;
private Person person;
public Address()
{
}
public Address(String name)
{
this.name = name;
}
@Id
@GeneratedValue
@Column(name = "ADDRESS_ID")
public Integer getAddressId() {
return addressId;
}
public void setAddressId(Integer addressId) {
this.addressId = addressId;
}
@Column(name = "ADDRESS_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "P_ID")
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
@Override
public String toString() {
return this.addressId + "\t" + this.name;
}
}B.onetomany端是owner
注意address中joincolumn的insertable和updatable 为false
@Entity
@Table(name = "PERSON")
public class Person {
private Integer id;
private String name;
private Set<Address> addressSet = new HashSet<Address>(0);
public Person() {
}
public Person(String name, Set<Address> addSet) {
this.name = name;
this.addressSet = addSet;
}
@Id
@GeneratedValue
@Column(name = "PERSON_ID")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(name = "PERSON_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinColumn(name = "P_ID")
public Set<Address> getAddressSet() {
return addressSet;
}
public void setAddressSet(Set<Address> addressSet) {
this.addressSet = addressSet;
}
@Override
public String toString() {
return this.id + "\t" + this.name;
}
}@Entity
@Table(name = "ADDRESS")
public class Address {
private Integer addressId;
private String name;
private Person person;
public Address()
{
}
public Address(String name)
{
this.name = name;
}
@Id
@GeneratedValue
@Column(name = "ADDRESS_ID")
public Integer getAddressId() {
return addressId;
}
public void setAddressId(Integer addressId) {
this.addressId = addressId;
}
@Column(name = "ADDRESS_NAME")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "person_fk", insertable=false, updatable=false)
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
@Override
public String toString() {
return this.addressId + "\t" + this.name;
}
}测试
1.插入Person及关联的Address,hibernate生成的的sql语句为
manytoone端为owner时
Hibernate: insert into PERSON (PERSON_ID, PERSON_NAME) values (null, ?) Hibernate: insert into ADDRESS (ADDRESS_ID, ADDRESS_NAME, person_fk) values (null, ?, ?) Hibernate: insert into ADDRESS (ADDRESS_ID, ADDRESS_NAME, person_fk) values (null, ?, ?)
onetomany端为owner时
Hibernate: insert into PERSON (PERSON_ID, PERSON_NAME) values (null, ?) Hibernate: insert into ADDRESS (ADDRESS_ID, ADDRESS_NAME) values (null, ?) Hibernate: insert into ADDRESS (ADDRESS_ID, ADDRESS_NAME) values (null, ?) Hibernate: update ADDRESS set person_fk=? where ADDRESS_ID=? Hibernate: update ADDRESS set person_fk=? where ADDRESS_ID=?
2.删除Address时，
manytoone端为owner时
Hibernate: delete from ADDRESS where ADDRESS_ID=? Hibernate: delete from ADDRESS where ADDRESS_ID=? Hibernate: delete from PERSON where PERSON_ID=?
onetomany端为owner时
Hibernate: update ADDRESS set person_fk=null where person_fk=? Hibernate: delete from ADDRESS where ADDRESS_ID=? Hibernate: delete from ADDRESS where ADDRESS_ID=? Hibernate: delete from PERSON where PERSON_ID=?
3.删除Person同删除Address相同
显然，onetomany端为owner时，会生成更多sql， 故hibernatedoc有如下说明：
引用
This solution is obviously not optimized from the number of needed statements
参考：
http://docs.jboss.org/ejb3/app-server/HibernateAnnotations/reference/en/html_single/index.html#d0e949