Java/JPA/Delete

Материал из Java эксперт
Перейти к: навигация, поиск

Delete Entities

   <source lang="java">

File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {

 public static void main(String[] a) throws Exception {
   JPAUtil util = new JPAUtil();
   EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService");
   EntityManager em = emf.createEntityManager();
   ProfessorService service = new ProfessorService(em);
   em.getTransaction().begin();
   service.removeDepartment();
   //service.removeDepartment2();
   
   util.checkData("select * from Professor");
   util.checkData("select * from Department");
   em.getTransaction().rumit();
   em.close();
   emf.close();
 }

}

File: Department.java

import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; @Entity public class Department {

   @Id
   private int id;
   private String name;
   @OneToMany(mappedBy="department")
   private Collection<Professor> employees;
   public Department() {
       employees = new ArrayList<Professor>();
   }
   
   public int getId() {
       return id;
   }
   
   public String getName() {
       return name;
   }
   
   public Collection<Professor> getProfessors() {
       return employees;
   }
   public String toString() {
       return "Department no: " + getId() + 
              ", name: " + getName();
   }

}

File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {

 Statement st;
 
 public JPAUtil() throws Exception{
   Class.forName("org.hsqldb.jdbcDriver");
   System.out.println("Driver Loaded.");
   String url = "jdbc:hsqldb:data/tutorial";
   Connection conn = DriverManager.getConnection(url, "sa", "");
   System.out.println("Got Connection.");
   st = conn.createStatement();
 }
 public void executeSQLCommand(String sql) throws Exception {
   st.executeUpdate(sql);
 }
 public void checkData(String sql) throws Exception {
   ResultSet rs = st.executeQuery(sql);
   ResultSetMetaData metadata = rs.getMetaData();
   for (int i = 0; i < metadata.getColumnCount(); i++) {
     System.out.print("\t"+ metadata.getColumnLabel(i + 1)); 
   }
   System.out.println("\n----------------------------------");
   while (rs.next()) {
     for (int i = 0; i < metadata.getColumnCount(); i++) {
       Object value = rs.getObject(i + 1);
       if (value == null) {
         System.out.print("\t       ");
       } else {
         System.out.print("\t"+value.toString().trim());
       }
     }
     System.out.println("");
   }
 }

}

File: Professor.java

import java.util.ArrayList; import java.util.Collection; import java.util.Date; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.ManyToOne; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Temporal; import javax.persistence.TemporalType; @Entity public class Professor {

   @Id
   private int id;
   private String name;
   private long salary;
   @Temporal(TemporalType.DATE)
   private Date startDate;
   
   @ManyToOne
   private Professor manager;
   
   @OneToMany(mappedBy="manager")
   private Collection<Professor> directs;
   @ManyToOne
   private Department department;
   
   @ManyToMany 
   private Collection<Project> projects;
   public Professor() {
       projects = new ArrayList<Project>();
       directs = new ArrayList<Professor>();
   }
   public int getId() {
       return id;
   }
   
   public String getName() {
       return name;
   }
   public long getSalary() {
       return salary;
   }
   public Date getStartDate() {
       return startDate;
   }
   
   public Department getDepartment() {
       return department;
   }
   
   public Collection<Professor> getDirects() {
       return directs;
   }
   
   public Professor getManager() {
       return manager;
   }
   public Collection<Project> getProjects() {
       return projects;
   }
   
   public String toString() {
       return "Professor " + getId() + 
              ": name: " + getName() +
              ", salary: " + getSalary() +
              ", dept: " + ((getDepartment() == null) ? null : getDepartment().getName());
   }

}

File: ProfessorService.java import java.util.List; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {

 protected EntityManager em;
 public ProfessorService(EntityManager em) {
   this.em = em;
 }
 public void removeDepartment() {
   em.createQuery(
       "DELETE FROM Department d "
           + "WHERE d.name IN ("CA", "NY30")").executeUpdate();
 }
 public void removeDepartment2() {
   em.createQuery(
       "UPDATE Professor e " +
       "SET e.department = null " +
       "WHERE e.department.name IN ("CA13", "CA19", "NY30")"

).executeUpdate();

 }

}

File: Project.java

import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToMany; @Entity public class Project {

   @Id
   protected int id;
   protected String name;
   @ManyToMany(mappedBy="projects")
   private Collection<Professor> employees;
   public Project() {
       employees = new ArrayList<Professor>();
   }
   public int getId() {
       return id;
   }
   
   public String getName() {
       return name;
   }
   
   public Collection<Professor> getProfessors() {
       return employees;
   }
   
   public String toString() {
       return "Project id: " + getId() + ", name: " + getName();
   }

}


File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"

            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0">
 <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL">
   <properties>
     <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
     <property name="hibernate.hbm2ddl.auto" value="update"/>
     <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>
     <property name="hibernate.connection.username" value="sa"/>
     <property name="hibernate.connection.password" value=""/>
     <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/>
   </properties>
 </persistence-unit>

</persistence>


      </source>
   
  
 
  



Delete With Condition

   <source lang="java">

File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {

 public static void main(String[] a) throws Exception {
   JPAUtil util = new JPAUtil();
   EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService");
   EntityManager em = emf.createEntityManager();
   ProfessorService service = new ProfessorService(em);
   em.getTransaction().begin();
   service.executeUpdate("DELETE FROM Professor e WHERE e.department IS NULL");
   em.getTransaction().rumit();
   em.close();
   emf.close();
 }

}

File: Address.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();
   }

}

File: Department.java

import java.util.HashSet; import java.util.Set; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; @Entity public class Department {

   @Id
   private int id;
   private String name;
   @OneToMany(mappedBy="department")
   private Set<Professor> employees = new HashSet<Professor>();
   public int getId() {
       return id;
   }
   
   public void setId(int deptNo) {
       this.id = deptNo;
   }
   
   public String getName() {
       return name;
   }
   
   public void setName(String deptName) {
       this.name = deptName;
   }
   
   public Set<Professor> getProfessors() {
       return employees;
   }
   public String toString() {
       return "Department no: " + getId() + 
              ", name: " + getName();
   }

}

File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {

 Statement st;
 
 public JPAUtil() throws Exception{
   Class.forName("org.hsqldb.jdbcDriver");
   System.out.println("Driver Loaded.");
   String url = "jdbc:hsqldb:data/tutorial";
   Connection conn = DriverManager.getConnection(url, "sa", "");
   System.out.println("Got Connection.");
   st = conn.createStatement();
 }
 public void executeSQLCommand(String sql) throws Exception {
   st.executeUpdate(sql);
 }
 public void checkData(String sql) throws Exception {
   ResultSet rs = st.executeQuery(sql);
   ResultSetMetaData metadata = rs.getMetaData();
   for (int i = 0; i < metadata.getColumnCount(); i++) {
     System.out.print("\t"+ metadata.getColumnLabel(i + 1)); 
   }
   System.out.println("\n----------------------------------");
   while (rs.next()) {
     for (int i = 0; i < metadata.getColumnCount(); i++) {
       Object value = rs.getObject(i + 1);
       if (value == null) {
         System.out.print("\t       ");
       } else {
         System.out.print("\t"+value.toString().trim());
       }
     }
     System.out.println("");
   }
 }

}

File: Phone.java

import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Phone {

   @Id
   private long id;
   private String number;
   private String type;
   @OneToOne Professor employee;
   
   public long getId() {
       return id;
   }
   
   public void setId(long id) {
       this.id = id;
   }
   
   public String getNumber() {
       return number;
   }
   
   public void setNumber(String phoneNo) {
       this.number = phoneNo;
   }
   
   public String getType() {
       return type;
   }
   
   public void setType(String phoneType) {
       this.type = phoneType;
   }
   
   public Professor getProfessor() {
       return employee;
   }
   public void setProfessor(Professor employee) {
       this.employee = employee;
   }
   public String toString() {
       return "Phone id: " + getId() + 
              ", no: " + getNumber() +
              ", type: " + getType();
   }

}

File: Professor.java import java.util.ArrayList; import java.util.Collection; import java.util.Date; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.OneToOne; import javax.persistence.Temporal; import javax.persistence.TemporalType; @Entity public class Professor {

   @Id
   private int id;
   private String name;
   private long salary;
   @Temporal(TemporalType.DATE)
   private Date startDate;
   
   @OneToOne
   private Address address;
   
   @OneToMany(mappedBy="employee")
   private Collection<Phone> phones = new ArrayList<Phone>();
   
   @ManyToOne
   private Department department;
   
   @ManyToOne
   private Professor manager;
   
   @OneToMany(mappedBy="manager")
   private Collection<Professor> directs = new ArrayList<Professor>();
   
   @ManyToMany(mappedBy="employees")
   private Collection<Project> projects = new ArrayList<Project>();
   public int getId() {
       return id;
   }
   
   public void setId(int empNo) {
       this.id = empNo;
   }
   
   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 Date getStartDate() {
       return startDate;
   }
   public void setStartDate(Date startDate) {
       this.startDate = startDate;
   }
   
   public Collection<Phone> getPhones() {
       return phones;
   }
   
   public void addPhone(Phone phone) {
       if (!getPhones().contains(phone)) {
           getPhones().add(phone);
           if (phone.getProfessor() != null) {
               phone.getProfessor().getPhones().remove(phone);
           }
           phone.setProfessor(this);
       }
   }
   
   public Department getDepartment() {
       return department;
   }
   
   public void setDepartment(Department department) {
       if (this.department != null) {
           this.department.getProfessors().remove(this);
       }
       this.department = department;
       this.department.getProfessors().add(this);
   }
   
   public Collection<Professor> getDirects() {
       return directs;
   }
   
   public void addDirect(Professor employee) {
       if (!getDirects().contains(employee)) {
           getDirects().add(employee);
           if (employee.getManager() != null) {
               employee.getManager().getDirects().remove(employee);
           }
           employee.setManager(this);
       }
   }
   
   public Professor getManager() {
       return manager;
   }
   
   public void setManager(Professor manager) {
       this.manager = manager;
   }
   public Collection<Project> getProjects() {
       return projects;
   }
   
   public void addProject(Project project) {
       if (!getProjects().contains(project)) {
           getProjects().add(project);
       }
       if (!project.getProfessors().contains(this)) {
           project.getProfessors().add(this);
       }
   }
   
   public Address getAddress() {
       return address;
   }
   
   public void setAddress(Address address) {
       this.address = address; 
   }
   
   public String toString() {
       return "Professor " + getId() + 
              ": name: " + getName() +
              ", salary: " + getSalary() +
              ", phones: " + getPhones() +
              ", managerNo: " + ((getManager() == null) ? null : getManager().getId()) +
              ", deptNo: " + ((getDepartment() == null) ? null : getDepartment().getId());
   }

}

File: ProfessorService.java import java.util.List; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {

 protected EntityManager em;
 public ProfessorService(EntityManager em) {
   this.em = em;
 }
 public List executetQuery(String queryString) {
   Query query = em.createQuery(queryString);
   return query.getResultList();
 }
 public void executeUpdate(String updateString) {
   em.createQuery(updateString).executeUpdate();
 }

}

File: Project.java

import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Inheritance; import javax.persistence.ManyToMany; @Entity @Inheritance public class Project {

   @Id
   protected int id;
   protected String name;
   @ManyToMany
   protected Collection<Professor> employees = new ArrayList<Professor>();
   
   public int getId() {
       return id;
   }
   
   public void setId(int projectNo) {
       this.id = projectNo;
   }
   
   public String getName() {
       return name;
   }
   
   public void setName(String projectName) {
       this.name = projectName;
   }
   
   public Collection<Professor> getProfessors() {
       return employees;
   }
   
   public void addProfessor(Professor employee) {
       if (!getProfessors().contains(employee)) {
           getProfessors().add(employee);
       }
       if (!employee.getProjects().contains(this)) {
           employee.getProjects().add(this);
       }
   }
   
   public String toString() {
       return getClass().getName().substring(getClass().getName().lastIndexOf(".")+1) + 
               " no: " + getId() + 
               ", name: " + getName();
   }

}


File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"

            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0">
 <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL">
   <properties>
     <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
     <property name="hibernate.hbm2ddl.auto" value="update"/>
     <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>
     <property name="hibernate.connection.username" value="sa"/>
     <property name="hibernate.connection.password" value=""/>
     <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/>
   </properties>
 </persistence-unit>

</persistence>


      </source>
   
  
 
  



Remove An Entity

   <source lang="java">

File: Professor.java

import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Professor {

 @Id
 private int id;
 private String name;
 private long salary;
 public Professor() {
 }
 public Professor(int id) {
   this.id = id;
 }
 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 "Professor id: " + getId() + " name: " + getName() + " salary: " + getSalary();
 }

}

File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {

 protected EntityManager em;
 public ProfessorService(EntityManager em) {
   this.em = em;
 }
 public Professor createProfessor(int id, String name, long salary) {
   Professor emp = new Professor(id);
   emp.setName(name);
   emp.setSalary(salary);
   em.persist(emp);
   return emp;
 }
 public void removeProfessor(int id) {
   Professor emp = findProfessor(id);
   if (emp != null) {
     em.remove(emp);
   }
 }
 public Professor raiseProfessorSalary(int id, long raise) {
   Professor emp = em.find(Professor.class, id);
   if (emp != null) {
     emp.setSalary(emp.getSalary() + raise);
   }
   return emp;
 }
 public Professor findProfessor(int id) {
   return em.find(Professor.class, id);
 }
 public Collection<Professor> findAllProfessors() {
   Query query = em.createQuery("SELECT e FROM Professor e");
   return (Collection<Professor>) query.getResultList();
 }

}

File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {

 Statement st;
 
 public JPAUtil() throws Exception{
   Class.forName("org.hsqldb.jdbcDriver");
   System.out.println("Driver Loaded.");
   String url = "jdbc:hsqldb:data/tutorial";
   Connection conn = DriverManager.getConnection(url, "sa", "");
   System.out.println("Got Connection.");
   st = conn.createStatement();
 }
 public void executeSQLCommand(String sql) throws Exception {
   st.executeUpdate(sql);
 }
 public void checkData(String sql) throws Exception {
   ResultSet rs = st.executeQuery(sql);
   ResultSetMetaData metadata = rs.getMetaData();
   for (int i = 0; i < metadata.getColumnCount(); i++) {
     System.out.print("\t"+ metadata.getColumnLabel(i + 1)); 
   }
   System.out.println("\n----------------------------------");
   while (rs.next()) {
     for (int i = 0; i < metadata.getColumnCount(); i++) {
       Object value = rs.getObject(i + 1);
       if (value == null) {
         System.out.print("\t       ");
       } else {
         System.out.print("\t"+value.toString().trim());
       }
     }
     System.out.println("");
   }
 }

}

File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {

 public static void main(String[] a) throws Exception {
   JPAUtil util = new JPAUtil();
   EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService");
   EntityManager em = emf.createEntityManager();
   ProfessorService service = new ProfessorService(em);
   em.getTransaction().begin();
   Professor emp = service.createProfessor(158, "AAA", 45000);
   em.getTransaction().rumit();
   System.out.println("Persisted " + emp);
   util.checkData("select * from Professor");
   // remove an employee
   em.getTransaction().begin();
   service.removeProfessor(158);
   em.getTransaction().rumit();
   System.out.println("Removed Professor 158");
   util.checkData("select * from Professor");
   
   em.close();
   emf.close();
 }

}


File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"

            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0">
 <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL">
   <properties>
     <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
     <property name="hibernate.hbm2ddl.auto" value="update"/>
     <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>
     <property name="hibernate.connection.username" value="sa"/>
     <property name="hibernate.connection.password" value=""/>
     <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/>
   </properties>
 </persistence-unit>

</persistence>

      </source>
   
  
 
  



Removing With Relationships

   <source lang="java">

File: ParkingSpace.java

import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToOne; import javax.persistence.Table; @Entity @Table(name="PARKING_SPACE") public class ParkingSpace {

   @Id
   private int id;
   private int lot;
   private String location;
   @OneToOne(mappedBy="parkingSpace")
   private Professor employee;
   public int getId() {
       return id;
   }
   
   public void setId(int id) {
       this.id = id;
   }
   public int getLot() {
       return lot;
   }
   public void setLot(int lot) {
       this.lot = lot;
   }
   
   public String getLocation() {
       return location;
   }
   
   public void setLocation(String deptName) {
       this.location = deptName;
   }
   public Professor getProfessor() {
       return employee;
   }
   public void setProfessor(Professor employee) {
       this.employee = employee;
   }
   
   public String toString() {
       return "ParkingSpace id: " + getId() + " lot: " + getLot() +
              ", location: " + getLocation();
   }

}

File: Professor.java

import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; @Entity public class Professor {

   @Id
   private int id;
   private String name;
   
   @OneToOne 
   @JoinColumn(name="PSPACE_ID") 
   private ParkingSpace parkingSpace;
   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 ParkingSpace getParkingSpace() {
       return parkingSpace;
   }
   
   public void setParkingSpace(ParkingSpace parkingSpace) {
       this.parkingSpace = parkingSpace;
   }
   public String toString() {
       return "Professor id: " + getId() + " name: " + getName() + 
              " with " + getParkingSpace();
   }

}

File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; public class ProfessorService {

 protected EntityManager em;
 public ProfessorService(EntityManager em) {
   this.em = em;
 }
 public void removeParkingSpace(int empId) {
   Professor emp = em.find(Professor.class, empId);
   emp.setParkingSpace(null);
   em.remove(emp.getParkingSpace());
 }
 public void removeParkingSpaceWithFailure(int empId) {
   Professor emp = em.find(Professor.class, empId);
   em.remove(emp.getParkingSpace());
 }
 public Collection<Professor> findAllProfessors() {
   return (Collection<Professor>) em.createQuery("SELECT e FROM Professor e").getResultList();
 }

}

File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {

 Statement st;
 
 public JPAUtil() throws Exception{
   Class.forName("org.hsqldb.jdbcDriver");
   System.out.println("Driver Loaded.");
   String url = "jdbc:hsqldb:data/tutorial";
   Connection conn = DriverManager.getConnection(url, "sa", "");
   System.out.println("Got Connection.");
   st = conn.createStatement();
 }
 public void executeSQLCommand(String sql) throws Exception {
   st.executeUpdate(sql);
 }
 public void checkData(String sql) throws Exception {
   ResultSet rs = st.executeQuery(sql);
   ResultSetMetaData metadata = rs.getMetaData();
   for (int i = 0; i < metadata.getColumnCount(); i++) {
     System.out.print("\t"+ metadata.getColumnLabel(i + 1)); 
   }
   System.out.println("\n----------------------------------");
   while (rs.next()) {
     for (int i = 0; i < metadata.getColumnCount(); i++) {
       Object value = rs.getObject(i + 1);
       if (value == null) {
         System.out.print("\t       ");
       } else {
         System.out.print("\t"+value.toString().trim());
       }
     }
     System.out.println("");
   }
 }

}

File: Main.java import java.util.Collection; import java.util.Iterator; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {

 public static void main(String[] a) throws Exception {
   JPAUtil util = new JPAUtil();
   EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService");
   EntityManager em = emf.createEntityManager();
   ProfessorService service = new ProfessorService(em);
   em.getTransaction().begin();
   service.removeParkingSpace(1);
   service.removeParkingSpaceWithFailure(1);
   
   util.checkData("select * from Professor");
   em.getTransaction().rumit();
   em.close();
   emf.close();
 }

}


File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"

            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0">
 <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL">
   <properties>
     <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
     <property name="hibernate.hbm2ddl.auto" value="update"/>
     <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/>
     <property name="hibernate.connection.username" value="sa"/>
     <property name="hibernate.connection.password" value=""/>
     <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/>
   </properties>
 </persistence-unit>

</persistence>

      </source>