hibernate向数据库添加出现的问题

tangzhi

org.hibernate.exception.DataException: could not insert: [org.teng.beans.Teng]
        org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:77)
        org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
        org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:1986)
        org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2405)
        org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:37)
        org.hibernate.engine.ActionQueue.execute(ActionQueue.java:248)
        org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:269)
        org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
        org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101)
        org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
        org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
        org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
        org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
        org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
        org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:530)
        org.hibernate.impl.SessionImpl.save(SessionImpl.java:518)
        org.hibernate.impl.SessionImpl.save(SessionImpl.java:514)
        org.teng.daos.TengDAO.adduser(TengDAO.java:12)
        org.teng.servlet.Add.doPost(Add.java:64)
        javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
        javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

数据库 是SQL2000,