# models.py
class AuthorManager(models.Manager): # 新建一个类，继承自models.Manager
  def name_count(self, keywords): # 添加自定义的查询函数
   '''统计姓名中含有某些关键字的数量'''
    return self.filter(name__contains=keywords).count()
    
  def lt_age(self, age):
    '''查询年龄小于指定年龄的信息'''
    return self.filter(age__lt=age)

class Author(models.Model):
  objects = AuthorManager() # 使用创建的自定义类覆盖objects

  name = models.CharField(max_length=30, verbose_name='姓名')
  age = models.IntegerField(verbose_name='年龄')
  email = models.EmailField(null=True, verbose_name='邮箱')
  picture = models.ImageField(null=True, upload_to='static/upload/usring', verbose_name='用户头像')

  publisher = models.ManyToManyField(Publisher, null=True, verbose_name='出版社')

# views.py
def myself(request):
 '''自定义查询函数'''
 # 统计名字中包含王字的
  num = Author.objects.name_count(keywords='王') 
 
 # 查询年龄小于36的作者信息
  authors = Author.objects.lt_age(age=36)
  return render(request, 'name_count.html', locals())