乐观锁异常
session.save(classEntity);//级联操作
/*
for (StudentEntity student:studentEntity){
session.save(student);
}
*/只添加班级，系统通过级联添加学生就会报错javax.persistence.OptimisticLockException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)
但是只保存学生，系统就会自动级联保存班级这样就是正常的，
有大佬清楚问题吗？我代码块里只有一个session事务
