Question

Here is some entity:

@Entity
public class Forest {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;


    public Forest() {
    }

    public long getId() {
        return id;
    }

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

I want to insert some element in table forest:

public class Main {
private static EntityManagerFactory emf = 
       Persistence.createEntityManagerFactory("server");

    public static void main(String[] args) {

        EntityManager em = emf.createEntityManager();
        EntityTransaction trx = em.getTransaction();
        Forest forest = new Forest();


        trx.begin();
        em.persist(forest);
        trx.commit();

    }
}

Thrown exception:

Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: Table 'server.forest' doesn't exist

Caused by: org.hibernate.exception.SQLGrammarException: Table 'server.forest' doesn't exist

My persistence.xml file with settings:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
   <persistence-unit name="server">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>

      <properties>
          <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
          <property name="javax.persistence.jdbc.url"               value="jdbc:mysql://localhost:3306/server"/>
          <property name="javax.persistence.jdbc.user" value="root" />
          <property name="javax.persistence.jdbc.password" value="root" />
          <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
          <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
      </properties>
   </persistence-unit>
</persistence>

When I removed @GeneratedValue(strategy = GenerationType.AUTO) and set id for forest:
forest.setID(1), there was no exception and table has been generated. So, auto-generating of id is not working and I don’t know why.

Answer 1

According configuration there is org.hibernate.dialect.HSQLDialect used with MySQL database. Using MySQL dialect instead of one of HSQL likely helps. Likely InnoDB is used – if so, then MySQL5InnoDBDialect is way to go.