What does “org.hibernate.DuplicateMappingException” error mean?

Question

I\'m trying to force JPA/Hibernate to generate and use only lowercase tablenames. I\'ve implemented a NamingStrategy like this:

public class MyNamingStrategy ext         


        

Answer 1

Bogdan, thanks for posting this. I had a similar problem with case-sensitive table names for Unix/Windows portability using Hibernate/JPA/MySQL on Linux.

Like you, I set out to bind my table names as all lower-case by configuring a custom NamingStrategy in my META-INF/persistence.xml file:

<property name="hibernate.ejb.naming_strategy" value="my.package.LowerCaseNamingStrategy" />

I got the same exception: org.hibernate.DuplicateMappingException: Same physical table name... Through using the debugger, I had an epiphany that maybe I wasn't using DefaultNamingStrategy to begin with! So I changed my base class to org.hibernate.cfg.EJB3NamingStrategy. This is more appropriate when using JPA Annotations, I believe! Here was my final NamingStrategy:

package my.package;

import org.apache.commons.lang.StringUtils;
import org.hibernate.cfg.EJB3NamingStrategy;

public class LowerCaseNamingStrategy extends EJB3NamingStrategy {
    @Override
    public String classToTableName(String className) {
        return StringUtils.lowerCase(super.classToTableName(className));
    }

    @Override
    public String collectionTableName(String ownerEntity, String ownerEntityTable, String associatedEntity,
            String associatedEntityTable, String propertyName) {
        return StringUtils.lowerCase(super.collectionTableName(ownerEntity, ownerEntityTable, associatedEntity, associatedEntityTable, propertyName));
    }

    @Override
    public String logicalCollectionTableName(String tableName, String ownerEntityTable, String associatedEntityTable,
            String propertyName) {
        return StringUtils.lowerCase(super.logicalCollectionTableName(tableName, ownerEntityTable, associatedEntityTable, propertyName));
    }

    @Override
    public String tableName(String tableName) {
        return StringUtils.lowerCase(super.tableName(tableName));
    }
}

PS the previous solution by dursun did not work for me.