How to connect postgresql in hibernate.cfg.xml

Question

I am trying to insert some data into postgresql through hibernate. However, there are not much tutorial about configurate hibernate with postgresql (I know, it should be similar to mysql =))

src/main/resources/hibernate.cfg.xml

<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.url">jdbc:postgresql://127.0.0.1:5432/myDatabase</property>
<property name="connection.username">myUser</property>
<property name="connection.password">myPassword</property>

<!-- JDBC connection pool (use the build-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

<!-- thread is the short name for org.hibernate.context.ThreadLocalSessionContext -->
<property name="current_session_context_class">thread</property>

<!-- Set "true" to show SQL statements -->
<property name="hibernate.show_sql">true</property>

<!-- mapping class using annotation -->
<mapping class="com.hib.entities.Student"></mapping>
</session-factory>

</hibernate-configuration>

src/main/java/

package com.hib.init;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class Hibernateutil {
private static final SessionFactory sessionF;
private static final ServiceRegistry serviceR;

static {
    Configuration conf = new Configuration();
    conf.configure();
    System.out.println("Begin");
    serviceR = new ServiceRegistryBuilder().applySettings(conf.getProperties()).buildServiceRegistry();
    System.out.println("Ready???");
    try {
        sessionF = conf.buildSessionFactory(serviceR);
        System.out.println("Success??");
    }catch(Exception e) {
        throw new ExceptionInInitializerError(e);
    }
}

public static SessionFactory getSeeionFactory() {
    return sessionF;
}
}

src/main/java package com.hib.entities;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table
public class Student {

@Id
@GeneratedValue
private Integer id;
private String firstName;

private Integer age;

public Student() {}

public Student(Integer id, String firstName, Integer age) {
    super();
    this.id = id;
    this.firstName = firstName;
    this.age = age;
}

public Integer getId() {
    return id;
}

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

public String getFirstName() {
    return firstName;
}

public void setFirstName(String firstName) {
    this.firstName = firstName;
}

public Integer getAge() {
    return age;
}

public void setAge(Integer age) {
    this.age = age;
}   
}

src/main/java

package com.hib.demo;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import com.hib.entities.Student;
import com.hib.init.Hibernateutil;

public class DemoFirst {

public static void main(String[] args) {
    SessionFactory sessionFactory = Hibernateutil.getSeeionFactory();
    Session session = sessionFactory.openSession();
    session.beginTransaction();

    Student student = new Student();
    student.setFirstName("Bob");
    student.setAge(26);

    session.save(student);
    session.getTransaction().commit();

    session.close();
}
}

And this is the error I got :

Success??
Hibernate: select nextval ('hibernate_sequence')
Aug 12, 2014 11:01:10 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 0, SQLState: 42P01
Aug 12, 2014 11:01:10 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: ERROR: relation "hibernate_sequence" does not exist
Position: 17
Exception in thread "main" org.hibernate.exception.SQLGrammarException: ERROR: relation        "hibernate_sequence" does not exist
Position: 17
at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:122)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129)
at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
at com.sun.proxy.$Proxy9.executeQuery(Unknown Source)
at org.hibernate.id.SequenceGenerator.generateHolder(SequenceGenerator.java:123)
at org.hibernate.id.SequenceGenerator.generate(SequenceGenerator.java:116)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:120)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:204)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:189)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:642)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:635)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:631)
at com.hib.demo.DemoFirst.main(DemoFirst.java:20)


Caused by: org.postgresql.util.PSQLException: ERROR: relation "hibernate_sequence" does not exist
Position: 17
at    org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2062)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1795)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:367)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:271)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122)
... 14 more

pom.xml

 <dependency>
    <groupId>postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>8.4-701.jdbc4</version>
</dependency>

Michael Zhavzharov · Accepted Answer · 2014-08-13 06:39:51Z

5

According to this thread you must set your Id annotation as follows:

@GeneratedValue(strategy = GenerationType.IDENTITY)

answered Aug 13, 2014 at 6:39

Michael Zhavzharov

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Vlad Mihalcea · Accepted Answer · 2014-08-13 06:46:31Z

2

You forgot to add the DDL auto generation property. You can use any of the following settings:

<property name="hibernate.hbm2ddl.auto" value="update">
<property name="hibernate.hbm2ddl.auto" value="create">
<property name="hibernate.hbm2ddl.auto" value="create-drop">

update is going to create and then simply update the DDL schema
create is going to create the schema if it doesn't exist
create-drop will create the schema when the SessionFactory is initialized and destroy it when the SessionFactory is destroyed. This is useful during integration testing.

answered Aug 13, 2014 at 6:46

Vlad Mihalcea

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Comments

Cortwave · Accepted Answer · 2014-08-13 06:37:34Z

1

You should make mapping beetwen table-entity class, column- field. For example (table and columns should exist) :

@Entity
@Table(name = "student")
public class Student {

@Id
@GeneratedValue
@Column(name = "id")
private Integer id;

@Column(name = "first_name")
private String firstName;

@Column(name = "age")
private Integer age;

answered Aug 13, 2014 at 6:37

Cortwave

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Comments

Mayur Gupta · Accepted Answer · 2014-08-13 06:49:40Z

Because you are using @GeneratedValue()

It will look for how the database that you are using generates ids. For MySql or HSQSL, there are increment fields that automatically increment. In Postgres or Oracle, they use sequence tables. Since you didn't specify a sequence table name, it will look for a sequence table named hibernate_sequence and use it for default. So you probably don't have such a sequence table in your database and now you get that error.

Either add a hibernate_sequence like

@GeneratedValue(strategy=SEQUENCE)

or your own sequence table and use the annotations to name your sequence table that you have like

@GeneratedValue(strategy=SEQUENCE, generator="student_id_seq")

Hope that helps

Nilesh Jadav · Accepted Answer · 2016-08-03 13:37:07Z

Connect to Postgresql by Hibernate -> configuration in hibernate.cfg.xml would be :

<session-factory>

    <!-- SQL dialect -->
    <!-- <property name="dialect">org.hibernate.dialect.H2Dialect</property> -->

    <!-- Database connection settings -->

    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
    <property name="connection.url">jdbc:postgresql://localhost:5432/db_name</property>
    <property name="connection.username">username</property>
    <property name="connection.password">db_assword</property>

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


    <!-- Disable the second-level cache -->
    <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

    <!-- Drop and re-create the database schema on startup -->
    <property name="hbm2ddl.auto">update</property>
    <!-- <property name="hbm2ddl.auto">validate</property> -->

    <!-- The mapping information of entities -->
    <!-- <mapping class="hibernate_example.envers.Book" /> -->
    <!-- <mapping class="hibernate_example.envers.Student" /> -->
    <!-- <mapping class="hibernate_example.envers.AuditEntity" /> -->


</session-factory>

Scott · Accepted Answer · 2018-06-05 15:34:25Z

0

Your id should look like:

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "my_id_gen")
@SequenceGenerator(name = "my_id_gen", sequenceName = "my_id_seq")
private Long id;

The sequenceName property should refer to the proper sequence in your database. If you created the column as sequence type, then it should be tableName_columnName_seq.

answered Jun 5, 2018 at 15:34

Scott

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