Question

hibernate mysql自动建表出错，原因是什么？

Employee.hbm.xml 的代码是：
<hibernate-mapping package="com.jwos.domain">
<class name="Employee" table="employee" >
<id name="id" column="id" type="java.lang.Integer" >
<generator class="increment"></generator></id>
<property name="name" type="java.lang.String">
<column name="name" not-null="false" />
</property>
<property name="email" type="java.lang.String">
<column name="email" not-null="false" />
</property>
<property name="hiredate" type="java.util.Date">
<column name="hiredate" />
</property>
</class>
</hibernate-mapping>

hibernate.cfg.xml代码是：
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.username">root</property>
<property name="connection.password">3131624</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hbm2dd1.auto">create</property>
<property name="show_sql">true</property>
<!-- 指定要管理的对象文件 -->
<mapping resource="com/jwos/domain/Employee.hbm.xml"/>
</session-factory>
</hibernate-configuration>

报错是Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not fetch initial value for increment generator

Answer 1

<property name="hbm2dd1.auto">create</property>
你这个hbm2ddl，最后一个字符是个数字1，不是字母l,应该是个字母l。

Answer 2

应该有个维护的变量,不过一般不用这个,在多个用户访问的时候会造成id重复

Answer 3

自增长是不是要设置一个初值？