django在读取数据库时未筛选到符合条件的记录会报错

（1）报错情况如下：

DoesNotExist: Publisher matching query does not exist.

 

（2）处理方法：

try:
    p = Publisher.objects.get(name='Apress')
except Publisher.DoesNotExist:
    print "Apress isn't in the database yet."
else:
    print "Apress is in the database."