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2010-06-01T05:02:39Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== AVG Projection ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.avg("Id"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>



== Group Field ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.groupProperty("id"));
projList.add(Projections.property("id"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>



== Hibernate demo code from Hibernate in action ==

== Projection: Count Distinct ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.countDistinct("Id"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>



== Projection: Max ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.max("Id"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>



== Projection: Min ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.min("Id"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>



== Scalar SQL Query ==

File: Main.java



<source lang="java">
import java.util.List;
import org.hibernate.Hibernate;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table Product(id int, name varchar, description varchar, price decimal(6,2), supplierid int)");

hibernateUtil
.executeSQLCommand("create table Supplier (id int , name varchar)");
hibernateUtil
.executeSQLCommand("create table Software(id int, name varchar, description varchar, price decimal(6,2), supplierid int, version varchar)");

Session session = hibernateUtil.getSession();
Supplier superCorp = new Supplier();
superCorp.setName("Supplier1");
session.save(superCorp);

Supplier megaInc = new Supplier();
megaInc.setName("Supplier2");
session.save(megaInc);
Product mouse = new Product("Product1","first product", 20.0);
mouse.setSupplier(superCorp);
superCorp.getProducts().add(mouse);
session.flush();
Product mouse2 = new Product("Product2","second product", 22.0);
mouse2.setSupplier(superCorp);
superCorp.getProducts().add(mouse2);

Product keyboard = new Product("Product3", "third product", 30.0);
keyboard.setSupplier(megaInc);
megaInc.getProducts().add(keyboard);
Software webBrowser = new Software("Web Browser","new browser", 75.0, "2.0");
webBrowser.setSupplier(superCorp);
superCorp.getProducts().add(webBrowser);
Software email = new Software("Email","email client", 49.99, "4.1 Edition");
email.setSupplier(megaInc);
megaInc.getProducts().add(email);
session.flush();

String sql = "select avg(product.price) as avgPrice from Product product";

SQLQuery query = session.createSQLQuery(sql);
query.addScalar("avgPrice",Hibernate.DOUBLE);
List results = query.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from Product");
hibernateUtil.checkData("select * from Software");
hibernateUtil.checkData("select * from Supplier");
}
}</source>



== Select Specific Fields in a Entity with Criteria and Projections ==

File: Main.java



<source lang="java">
import java.util.Date;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.ProjectionList;
import org.hibernate.criterion.Projections;
public class Main {
public static void main(String[] args) throws Exception {
HibernateUtil hibernateUtil = new HibernateUtil();
hibernateUtil
.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
Session session = hibernateUtil.getSession();
Survey survey = new Survey();
survey.setName("Survey");
survey.setPurchaseDate(new Date());
session.save(survey);

survey = new Survey();
survey.setName("Survey1");
survey.setPurchaseDate(new Date());
session.save(survey);

session.flush();

Criteria crit = session.createCriteria(Survey.class);
ProjectionList projList = Projections.projectionList();
projList.add(Projections.property("Id"));
projList.add(Projections.property("name"));
crit.setProjection(projList);

List results = crit.list();
System.out.println(results);

session.close();
hibernateUtil.checkData("select * from survey");
}
}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010