what is hibernate saveOrUpdate

Difference between hibernate‘s save,update and saveOrUpdate() methods. These are the data insertions methods and they are called on the session object.

save – save method stores an object into the database. That means it insert an entry if the identifier doesn’t exist, else it will throw error. If the primary key already present in the table, it cannot be inserted.

update – update method in the hibernate is used for updating the object using identifier. If the identifier is missing or doesn’t exist, it will throw exception.

saveOrUpdate – This method calls save() or update() based on the operation. If the identifier exists, it will call update method else the save method will be called.

saveOrUpdate – Cascade=”true”  – saves the object graph of the composition object as well.

The sample code to understand save, update, saveOrUpdate with cascade :

/////////////////////////////////////////////////////////////////////////

import java.util.*;

import org.hibernate.*;
import org.hibernate.criterion.*;

public class SimpleRetrieveTest {

public static void main(String[] args) {
HibernateUtil.setup(“create table EVENTS ( uid int, name VARCHAR, start_Date date, duration int, location_id int);”);
HibernateUtil.setup(“create table locations ( uid int, name VARCHAR, street_address VARCHAR, city VARCHAR, state VARCHAR, zip_Code VARCHAR);”);

// hibernate code start
Session session = HibernateUtil.currentSession();
Transaction tx = session.beginTransaction();

Location location = new Location();
location.setName(“India”);
location.getAddress().setStreetAddress(“St.”);
location.getAddress().setCity(“Pune”);
location.getAddress().setState(“Maharastra”);
location.getAddress().setZipCode(“411014”);

Event event = new Event();
event.setName(“Annual Meeting”);
event.setDuration(60);
event.setStartDate(createDate(2011, 11, 1));
event.setLocation(location);

//        session.save(location); location object will saved automatically with cascade update property.
session.save(event);
//        session.save(location); location object will saved automatically with cascade update property.

tx.commit();
HibernateUtil.closeSession();

HibernateUtil.sessionFactory.close();

HibernateUtil.checkData(“select * from events”);
HibernateUtil.checkData(“select * from locations”);
// hibernate code end
}
private static Date createDate(int year, int month, int day) {
Calendar calendar = Calendar.getInstance();
calendar.set(year, month, day);
return calendar.getTime();
}

}

/////////////////////////////////////////////////////////////////////////

import java.io.Serializable;

public class Location implements Serializable{
private Long id;
private String name;
private Address address = new Address();

public Location(String name) { this.name = name;}
public Location() { }

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 Address getAddress() { return address; }
public void setAddress(Address address) { this.address = address;}
}

/////////////////////////////////////////////////////////////////////////

<?xml version=“1.0”?>
<!DOCTYPE hibernate-mapping PUBLIC
“-//Hibernate/Hibernate Mapping DTD 3.0//EN”
http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd&#8221;>

<hibernate-mapping >
<class name=“Location” table=“locations”>
<id name=“id” column=“uid” type=“long”>
<generator class=“increment”/>
</id>
<property name=“name” type=“string”/>
<component name=“address” class=“Address” >
<property name=“streetAddress” column=“street_address” type=“string”/>
<property name=“city” type=“string”/>
<property name=“state” type=“string”/>
<property name=“zipCode” column=“zip_code” type=“string”/>
</component>
</class>
</hibernate-mapping>

/////////////////////////////////////////////////////////////////////////

<?xml version=‘1.0‘ encoding=‘utf-8‘?>
<!DOCTYPE hibernate-configuration PUBLIC
“-//Hibernate/Hibernate Configuration DTD 3.0//EN”
http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd&#8221;>

<hibernate-configuration>

<session-factory>

<!– Database connection settings –>
<property name=“connection.driver_class”>org.hsqldb.jdbcDriver</property>
<property name=“connection.url”>jdbc:hsqldb:data/tutorial</property>
<property name=“connection.username”>sa</property>
<property name=“connection.password”></property>

<!– JDBC connection pool (use the built-in) –>
<property name=“connection.pool_size”>1</property>

<!– SQL dialect –>
<property name=“dialect”>org.hibernate.dialect.HSQLDialect</property>

<!– Echo all executed SQL to stdout –>
<property name=“show_sql”>true</property>

<mapping resource=“Event.hbm.xml”/>
<mapping resource=“Location.hbm.xml”/>
</session-factory>

</hibernate-configuration>

/////////////////////////////////////////////////////////////////////////

import java.io.Serializable;
import java.util.Date;

public class Event implements Serializable {
private Long id;
private int duration;
private String name;
private Date startDate;
private Location location;

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 Date getStartDate() { return startDate; }
public void setStartDate(Date startDate) {
this.startDate = startDate;
}

public int getDuration() { return duration; }
public void setDuration(int duration) {
this.duration = duration;
}

public Location getLocation() { return location; }
public void setLocation(Location location) {
this.location = location;
}

public Event() { }
public Event(String name) { this.name = name; }

}

/////////////////////////////////////////////////////////////////////////

<?xml version=“1.0”?>
<!DOCTYPE hibernate-mapping PUBLIC
“-//Hibernate/Hibernate Mapping DTD 3.0//EN”
http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd&#8221;>

<hibernate-mapping >
<class name=“Event” table=“events”>
<id name=“id” column=“uid” type=“long”>
<generator class=“increment”/>
</id>
<property name=“name” type=“string”/>
<property name=“startDate” column=“start_date”
type=“date”/>
<property name=“duration” type=“integer”/>
<many-to-one name=“location” column=“location_id” class=“Location” cascade=“save-update” />
</class>
</hibernate-mapping>

/////////////////////////////////////////////////////////////////////////

public class Address {
private String streetAddress;
private String city;
private String state;
private String zipCode;

public String getStreetAddress() { return streetAddress; }
public void setStreetAddress(String streetAddress) { this.streetAddress = streetAddress;}

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 getZipCode() { return zipCode; }
public void setZipCode(String zipCode) { this.zipCode = zipCode; }

public void parse(String address) {
String[] parts = address.split(“\\.”);
setStreetAddress(parts[0] + “.”);
String[] remainingPart = parts[1].split(” “);
setCity(remainingPart[1].replaceAll(“,”, “”));
setState(remainingPart[2]);
setZipCode(remainingPart[3]);
}
}

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