Hibernate Apache Derby Custom Sequence

I am trying to investigate the generator class in the ID sequence generation of Hibernate.

I tried to use the sequence generator on a very simple mapping

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping 开发者_开发知识库package="com.test">
    <class name="Customer" table="Customer">
        <id name="id" column="ID" type="long">
            <generator class="sequence">
                <param name="sequence">CUSTOMER_SEQUENCE</param>
            </generator>
        </id>
        <property name="name" type="string" column="CUSTOMER_NAME" />
    </class>
</hibernate-mapping>

I am using apache derby, the ID column in the customer table is justa simple long datatype.

But when I try to execute a simple save, I am encountering below error.

Caused by: java.sql.SQLSyntaxErrorException: SEQUENCE 'CUSTOMER_SEQUENCE' does not exist. Does this mean that Apache Derby does not support Sequence Generation? Thanks

It seems that Derby doesn't support sequence generation. Quote from official Derby FAQ:

Derby supports generated "identity" columns; examples are in the Reference Guide. The IDENTITY_VAL_LOCAL function returns the most recently assigned number.

Work is underway to add SEQUENCE support to Derby 10.6.

Derby now supports sequence generation, as follows:

http://db.apache.org/derby/docs/10.8/ref/rrefsqljcreatesequence.html