package de.event;

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

@Entity
@Table(name = "events", catalog = "public")
public class Event {
    private Integer id;

    private String name;

    public Event() {
    }

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

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    public Integer getId() {
        return id;
    }

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

    @Column(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Transaction transInsert = session.beginTransaction();

Event e = new Event("Hibernate lernen!");

session.save(e);
transInsert.commit();

     [java] 15:15:19,478 ERROR JDBCExceptionReporter:78 - Attempt to insert null into a non-nullable column: column: ID table: EVENTS in statement [insert into public.events (id, name) values (null, ?)]
     [java] Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not insert: [de.event.Event]
     [java]    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
     [java]    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
     [java]    at org.hibernate.id.insert.AbstractSelectingDelegate.performInsert(AbstractSelectingDelegate.java:40)
     [java]    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2163)
     [java]    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2643)
     [java]    at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:51)
     [java]    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
     [java]    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:298)
     [java]    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:181)
     [java]    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:107)
     [java]    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:187)
     [java]    at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
     [java]    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:172)
     [java]    at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
     [java]    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
     [java]    at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:535)
     [java]    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:523)
     [java]    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:519)
     [java]    at de.business.EventManager.createAndStoreEvent(EventManager.java:19)
     [java]    at de.starter.Starter.main(Starter.java:9)
     [java] Caused by: java.sql.SQLException: Attempt to insert null into a non-nullable column: column: ID table: EVENTS in statement [insert into public.events (id, name) values (null, ?)]
     [java]    at org.hsqldb.jdbc.Util.throwError(Unknown Source)
     [java]    at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source)
     [java]    at org.hibernate.id.insert.AbstractSelectingDelegate.performInsert(AbstractSelectingDelegate.java:33)
     [java]    ... 17 more
     [java] Java Result: 1

<?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">

<hibernate-configuration>

    <session-factory>

        <!-- Database connection settings -->
        <property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
        <property name="connection.url">jdbc:hsqldb:file:../db/events</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>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

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

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
       
        <property name="hibernate.hbm2ddl.auto">validate</property>

    </session-factory>

</hibernate-configuration>