CODEWITHSUNDEEP
javahibernatemapping
James P.
James P.

Reputation: 19607

Using hibernate3 with existing tables

How can I configure Hibernate so it maps beans to some existing tables?

P.S: Each table should correspond with an entity.

Edit: Here is how I used Hibernate with autogenerated tables (taken from a web application). I'm still not clear on how to make the transition to some explicit mapping.

Example Entity bean

@Entity
@Table(name = "t1_category")
// PK is replaced by Long
// See generic definition in abstract class
public class Category extends BaseEntity<Long> {

    @Column(name="check_rsv")
    private String check;

    @Column(unique = true)
    private String name;
    private static final long serialVersionUID = 1L;

    public String getCheck() {
        return this.check;
    }

    public void setCheck(String check) {
        this.check = check;
    }   
    public String getName() {
        return this.name;
    }

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

}

applicationContext.xml/Spring

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:p="http://www.springframework.org/schema/p"
        xmlns:aop="http://www.springframework.org/schema/aop"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:jee="http://www.springframework.org/schema/jee"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
            http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:annotation-config />
    <context:component-scan base-package="***" />


    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="myPersistenceUnit" />
    </bean>

    <!-- Transaction manager for a single JPA EntityManagerFactory (alternative to JTA) -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" 
            p:entityManagerFactory-ref="entityManagerFactory"/>

    <tx:annotation-driven/> <!-- This apparently scans for annotations from the base-package value -->
</beans>

Persistence.xml

<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence">
    <persistence-unit name="myPersistenceUnit">

    <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <properties>
            <property name="hibernate.archive.autodetection" value="class"/>

          <property name="hibernate.connection.url"
                    value="jdbc:mysql://localhost:3306/***?autoReconnect=true"/>
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
            <property name="hibernate.connection.password" value="***"/>
            <property name="hibernate.connection.username" value="***"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>

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

            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
            <property name="hibernate.use_sql_comments" value="true"/>
        </properties>
    </persistence-unit>
</persistence>

Upvotes: 1

Views: 577

Answers (2)

malaverdiere
malaverdiere

Reputation: 1537

Hibernate annotations allow you to specify the table and column names. I'm adding the batch size and cache option as an extra, but that's not required for your question.

@Entity
@Table(name="BLAH")
@BatchSize(size=20)
@Cache(usage=CacheConcurrencyStrategy.TRANSACTIONAL)
public class Blah{

   @Id
   protected String theID;

   @Column(name="MEH")
   protected int meh;
}

Have a look at all the options in @Table @Column @Index and the @JoinColumn option for the one-to-many et al. relationships.

Upvotes: 1

Vladimir Dyuzhev
Vladimir Dyuzhev

Reputation: 18336

(What do you mean "fills in"? Map beans to tables? Then:)

Old way: create Hibernate *.hbm.xml per table/entity. Nothing extraordinary, did it in past.

New way: create beans, mark them up with the Hibernate annotations.

New new way: use JPA annotations for portable mapping and Hibernate as JPA implementation.

Upvotes: 1

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