Admin: 1 версия

2010-06-01T05:18:21Z

1 версия

в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

Новая страница

== Change Default Column Name ==

File: Student.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
public class Student {
@Id
@Column(name = "EMP_ID")
private int id = 0;
@Column(name = "COMM")
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 name) {
this.name = name;
}
public String toString() {
return "\n\nID:" + id + "\nName:" + name + "\n\n";
}
}</source>



== Compound Primary key ==

File: Student.java



<source lang="java">
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.IdClass;
@Entity
@IdClass(StudentId.class)
public class Student {
@Id private String country;
@Id
@Column(name="EMP_ID")
private int id;
private String name;

public int getId() {
return id;
}

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

public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
public String toString() {
return "Student id: " + getId() + " name: " + getName() +
" country: " + getCountry();
}
}
class StudentId implements Serializable {
private String country;
private int id;
public StudentId() {}
public StudentId(String country, int id) {
this.country = country;
this.id = id;
}
public String getCountry() { return country; }
public int getId() { return id; }
public boolean equals(Object o) {
return ((o instanceof StudentId) &&
country.equals(((StudentId)o).getCountry()) &&
id == ((StudentId) o).getId());
}
public int hashCode() {
return country.hashCode() + id;
}
}</source>



== Java Int Mapped To Integer ==

File: Student.java



<source lang="java">
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Student {
@Id
private int id = 0;
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 name) {
this.name = name;
}
public String toString() {
return "\n\nID:" + id + "\nName:" + name + "\n\n";
}
}</source>



== Java Long Mapped To Big Int ==

File: Student.java



<source lang="java">
import java.util.Date;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.Id;
@Entity
public class Student {
@Id
private long id = 0;

private String name;
private Date dateOfBirth = new Date();
@Enumerated(EnumType.STRING)
private Gender gender;

public Date getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(Date dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Gender getGender() {
return gender;
}
public void setGender(Gender gender) {
this.gender = gender;
}

}</source>



== Java String Mapped To Varchar ==

File: Gender.java



<source lang="java">
public enum Gender {
MALE, FEMALE
}</source>



== Set Column Length ==

File: Employee.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Entity
public class Employee {
@Id
@Column(length=40)
private String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}</source>



== Set Precision And Scale ==

File: Employee.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Employee {
@Id private int id;
private String name;
@Column(precision=8, scale=2)
private float hourlyRate;
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 float getHourlyRate() {
return hourlyRate;
}
public void setHourlyRate(float salary) {
this.hourlyRate = salary;
}
}</source>



== Specify Column Definition To Field ==

File: Employee.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Entity
public class Employee {
@Id
@Column(name="START_DATE", columnDefinition="DATE DEFAULT CURRENT_DATE")
private java.sql.Date startDate;

}</source>



== Unique, Not Nullable Column ==

File: Employee.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Employee {
@Id private int id;
@Column(unique=true, nullable=false)
private String name;
private long salary;
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 long getSalary() {
return salary;
}

public void setSalary(long salary) {
this.salary = salary;
}

public String toString() {
return "Employee id: " + getId() + " name: " + getName();
}
}</source>



== Use Varchar Type As Column Type ==

File: Employee.java



<source lang="java">
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Entity
public class Employee {
@Id
@Column(columnDefinition="VARCHAR(40)")
private String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010