How can I stop auto Scheme creation?

Question

If it is duplicate, my apology. I could not find an answer for my question.

I just start Hibernate. I have an issue is every time the program automatically delete the old shceme and creates new when it is running. For example, If I want to add records into database, I could not do it because the scheme will be recreate, so the histories will be deleted.

Here is my hbm.xml mapping file:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 22-Oct-2013 1:39:31 PM by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
    <class name="net.ys.hibernate.Equip" table="EQUIP">
        <id name="id" type="int">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="dis" type="java.lang.String" column="dis" />

        <property name="ref" type="java.lang.String" column="ref" />

        <property name="type" type="java.lang.String" column="type" />

    </class>
</hibernate-mapping>

hibernate.cfg.xml configuration file.

<?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>

        <!-- hibernate dialect -->

        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">pw</property>

        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/explorer_DB?useUnicode=true&amp;characterEncoding=GBK</property>
        <property name="hibernate.connection.username">username</property>
        <property name="hibernate.default_schema">explorer_DB</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Automatic schema creation(begin) -->
        <property name="hibernate.hbm2ddl.auto">create</property>
        <!-- Simple memory-only cache -->
        <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property>
        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- mapping files with external dependencies -->
        <mapping resource="net/ys/hibernate/Equip.hbm.xml"/>


    </session-factory>
</hibernate-configuration>

And addEquip method:

public Integer addEquip(String dis, String ref, String type){
        Session session = sessionFactory.openSession();
        currentSession = sessionFactory.getCurrentSession();
        Transaction tx = null;
        Integer equipID = null;

        try {
            tx = currentSession.beginTransaction(); //start a transaction

            Equip equip = new Equip(dis,ref,type);
            equipID = (Integer)currentSession.save(equip);
            tx.commit();
        } catch (HibernateException e) {
            if(tx!=null) tx.rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }

        return equipID;

    }
}

could someone help me to solve this issue? I just don't understand how to use getCurrentSession(), probably I am wrong in this point. Could you explain how hibernate works when we call getCurrentSession() for me? I really appreciate it.

Thank you so much

It seems you are creating session factory every time, could you check that? — Admit, Oct 23 '13 at 16:14
@Admit Hi Admit, in the addEquip(), open the openSession() first, and get CurrentSession. After that, calling currentSession.beginTransaction() starts a transaction. However, changing the create to none solves problem. — Eric, Oct 23 '13 at 16:30
you also could remove that, if you don't need schema creation at all(which is equals to none value). take a look at place where you create `sessionFactory`, since creating new factory for every request seems not efficient, and it seems it's a root of a problem. — Admit, Oct 23 '13 at 16:35
@Admit Yes, I do create sessionFactory in the main function. When program is running, it will create a sessionFactory. So the addEquip, listEquip, and updateEquip will define openSession() and getCurrentSession(). Basically, what's the logic when we use Hibernate. I don't have any exprience with it but I have some in JDBC. Thank you — Eric, Oct 23 '13 at 16:43

score 1 · Accepted Answer · edited May 23 '17 at 11:50

1

Change this property in your hibernate.cfg.xml file

current configuration

   <property name="hibernate.hbm2ddl.auto">create</property>

to

   <property name="hibernate.hbm2ddl.auto">none</property>

if no change required in database use.

<property name="hibernate.hbm2ddl.auto">validate</property>

How can I stop auto Scheme creation?

1 Answers1