hibernate mapping create table

Question

I wrote a mapping as like below:

<hibernate-mapping auto-import="true" default-lazy="false">
    <class name="com.saman.entity.hibernate.EmployeeEntity"
           table="Employee" optimistic-lock="version">

        <id name="id" type="java.lang.Integer" >
            <column name="Id" />
            <generator class="identity"/>
        </id>
        <timestamp name="version" source="db"/>
        <property  name="firstName">
            <column name="FirstName" sql-type="nvarchar(300)"/>
        </property>
        <property name="lastName">
            <column name="LastName" sql-type="nvarchar(300)"/>
        </property>
        <property name="employeeType">
            <column name="EmployeeType" sql-type="nvarchar(300)"/>
        </property>
        <!--
        <set name="shifts" table="Shifts" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="Id" not-null="true"/>
            </key>
            <one-to-many class="com.saman.entity.hibernate.ShiftEntity"/>
        </set>
        -->
        <properties name="u1" unique="true">
            <property name="firstName"/>
            <property name="lastName"/>
            <property name="employeeType"/>
        </properties>

    </class>
</hibernate-mapping>

when I run my application an error occurs like below:

2012-05-15 17:12:38,651 -- WARN -- Unsuccessful schema statement: create table Employee (Id integer not null auto_increment, version datetime not null, FirstName nvarchar(300), LastName nvarchar(300), EmployeeType nvarchar(300), primary key (Id), unique (firstName, lastName, employeeType)) com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Specified key was too long; max key length is 1000 bytes at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.Util.getInstance(Util.java:386) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2002) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2163) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2618) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1749) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1666) at com.mchange.v2.c3p0.impl.NewProxyStatement.executeUpdate(NewProxyStatement.java:64) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.executeSchemaStatement(LocalSessionFactoryBean.java:1115) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.executeSchemaScript(LocalSessionFactoryBean.java:1087) at org.springframework.orm.hibernate3.LocalSessionFactoryBean$1.doInHibernate(LocalSessionFactoryBean.java:942) at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406) at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:339) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.updateDatabaseSchema(LocalSessionFactoryBean.java:935) at org.springframework.orm.hibernate3.LocalSessionFactoryBean.afterSessionFactoryCreation(LocalSessionFactoryBean.java:883) at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:213) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1477) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1417) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:563) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425) at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139) at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:83) at Main.main(Main.java:18)

what is the problem with it?

Im using mysql and i run it on MAMP.

Post the full stack trace, and post the code causing this exception to be thrown. — JB Nizet

dimcookies dimcookies · Accepted Answer · 2012-05-15T13:01:42

Specified key was too long; max key length is 1000 bytes

This error means that your unique index (firstName, lastName, employeeType) is more than 1000 bytes which is the maximum. From mysql documentation

"UTF-8 encoding of the Unicode character set using one to three bytes per character"

Therefore you can see that you have three fields of 300 length so you may have an index of size 300* 3 * 3 = 2700 > 1000

hibernate mapping create table

2 Answers