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2010-06-01T05:18:43Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Bidirectional One To One Mapping ==

File: Main.java



<source lang="java">
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService");
static EntityManager em = emf.createEntityManager();
public static void main(String[] a) throws Exception {
em.getTransaction().begin();

Student student = new Student();
student.setName("Joe");
Address address = new Address();
address.setCity("city");
address.setStudent(student);
//em.persist(address);

student.setAddress(address);

em.persist(student);
em.flush();
em.getTransaction().rumit();

Query query = em.createQuery("SELECT e FROM Address e");
List<Address> list = (List<Address>) query.getResultList();
System.out.println(list.get(0).getStudent());

em.close();
emf.close();

Helper.checkData();
}
}</source>



== One To One Mapping Based On Table Based ID ==

File: Address.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.TableGenerator;
@Entity
public class Address {
@TableGenerator(name = "Address_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL", pkColumnValue = "Addr_Gen", initialValue = 10000, allocationSize = 100)
@Id
@GeneratedValue(strategy = GenerationType.TABLE, generator = "Address_Gen")
private int id;
private String street;
private String city;
private String state;
private String zip;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getStreet() {
return street;
}
public void setStreet(String address) {
this.street = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public String toString() {
return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity()
+ ", state: " + getState() + ", zip: " + getZip();
}
}</source>



== One To One Mapping Bidirectional ==

File: Student.java



<source lang="java">
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
@Entity
public class Student {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
@OneToOne (cascade=CascadeType.ALL)
@JoinColumn(name="DEPT_ID", unique= true, nullable=true, insertable=true, updatable=true)
private Department department;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

public Department getDepartment() {
return department;
}
public void setDepartment(Department department) {
this.department = department;
}
public String toString() {
return "\n\nID:" + id + "\nName:" + name + "\n\n" + department;
}
}</source>



== One To One Mapping Mapped By Field ==

File: Department.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
@Entity
public class Department {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
@OneToOne(mappedBy="department")
private Student student;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String deptName) {
this.name = deptName;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public String toString() {
return "Department id: " + getId() +
", name: " + getName();
}
}</source>



== One To One Mapping Primary Key As Join Column ==

File: Department.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.PrimaryKeyJoinColumn;
@Entity
public class Department {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
@OneToOne
@PrimaryKeyJoinColumn//a primary key column that is used as a foreign key to join to another table
private Student student;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String deptName) {
this.name = deptName;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public String toString() {
return "Department id: " + getId() +
", name: " + getName();
}
}</source>



== One To One Mapping With Cascading.All ==

File: Address.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Address {
@Id
private int id;
private String street;
private String city;
private String state;
private String zip;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getStreet() {
return street;
}
public void setStreet(String address) {
this.street = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public String toString() {
return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity()
+ ", state: " + getState() + ", zip: " + getZip();
}
}</source>



== One To One Mapping With Fetch Type Lazy ==

File: Address.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Address {
@Id
private int id;
private String street;
private String city;
private String state;
private String zip;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getStreet() {
return street;
}
public void setStreet(String address) {
this.street = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public String toString() {
return "Address id: " + getId() + ", street: " + getStreet() + ", city: " + getCity()
+ ", state: " + getState() + ", zip: " + getZip();
}
}</source>



== One To One Unidirectional ==

File: Department.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="Dept")
public class Department {
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
private String name;
public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String deptName) {
this.name = deptName;
}
public String toString() {
return "Department id: " + getId() +
", name: " + getName();
}
}</source>



== Retrieve One To One Mapped Entity ==

File: Student.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToOne;
@Entity
public class Student {
@Id
private int id;
private String name;
@OneToOne
private Address address;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
public String toString() {
return "\n\nID:" + id + "\nName:" + name + "\n\n";
}
}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010