hibernate报错
错误如下：
org.hibernate.exception.ConstraintViolationException: could not insert: [orm.Userinfo]
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43

Userinfo.hbm.xml代码：

<hibernate-mapping>

    <class name="orm.Userinfo" table="Userinfo" schema="dbo" catalog="woniu">

        <id name="id" type="java.lang.Integer">

            <column name="id" />

            <generator class="native" />

        </id>

        <property name="username" type="java.lang.String">

            <column name="username" length="50" not-null="true" />

        </property>

        <property name="password" type="java.lang.String">

            <column name="password" length="50" not-null="true" />

        </property>

        <property name="age" type="java.lang.Integer">

            <column name="age" />

        </property>

    </class>

</hibernate-mapping>

Insert.java代码：

package controller;



import orm.Userinfo;

import orm.UserinfoDAO;



public class Insert {

	

	public String execute(){

		Userinfo userinfo = new Userinfo();

		userinfo.setUsername("woniu");

		userinfo.setPassword("000123");

		userinfo.setAge(10);

		

		

		UserinfoDAO userinfoDAO = new UserinfoDAO();

		userinfoDAO.getSession().beginTransaction();

		userinfoDAO.attachDirty(userinfo);

		userinfoDAO.getSession().getTransaction().commit();

		userinfoDAO.getSession().close();

		return "";

		

	}

}