Hibernate demo code

Author: VanTamNguyen

code/hibernate-demo/db/schema.sql

@@ -11,5 +11,6 @@ CREATE TABLE IF NOT EXISTS bank_account(
     account VARCHAR(36) NOT NULL,
     balance INTEGER NOT NULL,
     person_id VARCHAR(36) NOT NULL,
-    FOREIGN KEY (person_id) REFERENCES person(id)
+    FOREIGN KEY (person_id) REFERENCES person(id),
+    CONSTRAINT account_unq UNIQUE(account)
 ) CHARACTER SET utf8;

code/hibernate-demo/src/main/java/com/tamco/hibernate/BankAccount.java

@@ -13,7 +13,7 @@ public class BankAccount {
     @GenericGenerator(name = "uuid", strategy = "uuid2")
     private String id;
 
-    @Column(name = "account")
+    @Column(name = "account", unique = true)
     private String account;
 
     @Column(name = "balance")

code/hibernate-demo/src/main/java/com/tamco/hibernate/Hibernate.java

@@ -1,9 +1,13 @@
 package com.tamco.hibernate;
 
+import org.hibernate.Criteria;
 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
 import org.hibernate.cfg.Configuration;
+import org.hibernate.criterion.Order;
+
+import java.util.List;
 
 public class Hibernate {
 
@@ -17,12 +21,51 @@ public static void main(String[] args) {
         configuration.addAnnotatedClass(BankAccount.class);
         sessionFactory = configuration.buildSessionFactory();
 
-        savePersonWithBankAcounts();
+        // Save some people with bank accounts
+        savePeopleWithBankAccounts();
+
+        // Order people by salary
+        orderPeopleBySalary();
+
+        // Clear database
+        deletePeople();
+    }
+
+    private static void deletePeople() {
+        Session session = null;
+        Transaction transaction = null;
+
+        try {
+            session = sessionFactory.openSession();
+            transaction = session.beginTransaction();
+
+            Criteria criteria = session.createCriteria(Person.class);
+            List<Person> people = criteria.list();
+            for (Person person : people) {
+                session.delete(person);
+            }
+
+            transaction.commit();
+            System.out.println("The database has been cleared");
+
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            e.printStackTrace();
+
+        } finally {
+            if (session != null) {
+                session.close();
+                System.out.println("Always close the session after done with database\n***************************************");
+            }
+        }
     }
 
-    private static void savePersonWithBankAcounts() {
+    private static void savePeopleWithBankAccounts() {
         Session session = null;
         Transaction transaction = null;
+
         try {
             session = sessionFactory.openSession();
             transaction = session.beginTransaction();
@@ -38,14 +81,19 @@ private static void savePersonWithBankAcounts() {
             session.save(account1);
             session.save(account2);
 
+            Person john = new Person("John Wick", 10000);
+            BankAccount account3 = new BankAccount("100013", 1000000);
+            account3.setPerson(john);
+            session.save(john);
+            session.save(account3);
+
             transaction.commit();
             System.out.println("Person with bank accounts has been saved!");
 
         } catch (Exception e) {
             if (transaction != null) {
                 transaction.rollback();
             }
-            e.printStackTrace();
             System.out.println("Person with bank accounts save failed! " + e.getMessage());
 
         } finally {
@@ -55,4 +103,35 @@ private static void savePersonWithBankAcounts() {
             System.out.println("Always close the session after done with database\n***************************************");
         }
     }
+
+    private static void orderPeopleBySalary() {
+        Session session = null;
+        Transaction transaction = null;
+
+        try {
+            session = sessionFactory.openSession();
+            transaction = session.beginTransaction();
+
+            Criteria criteria = session.createCriteria(Person.class);
+            criteria.addOrder(Order.desc("salary"));
+            List<Person> people = criteria.list();
+            for (Person person : people) {
+                System.out.println("Person[" + person.getName() + ", " + person.getSalary() + "]");
+            }
+
+            transaction.commit();
+            System.out.println("People have been ordered");
+
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+            System.out.println("Always close the session after done with database\n***************************************");
+        }
+    }
 }