class Banner(NewsBase):

    '''

    轮播图

    '''

    PRI_CHOICES = [     # 优先级的限制选择范围

        (1,'第一级'),

        (2,'第二级'),

        (3,'第三级'),

        (4,'第四级'),

        (5,'第五级'),

        (6,'第六级')

    ]

    image_url = models.CharField(verbose_name='图片url',max_length=200)

    priority = models.IntegerField(verbose_name='优先级',choices=PRI_CHOICES,default=6)   # choices参数,限制输入范围.

    news = models.OneToOneField('news',on_delete=models.CASCADE)

    class Meta:

        ordering = ['priority','-update_time']

        db_table = 'tb_banner'

        verbose_name = '轮播图'

        verbose_name_plural=verbose_name

    def __str__(self):

        return '<轮播图{}>'.format(self.id)