弦圈

提问你好，我使用的是django 1.2，然后我想知道如何对原生查询集(RawQuerySet)的行进行计数。惯例的.count()方法行不通。这是我的查询query = "SELECT *, ((ACOS(SIN(%s * PI() / 180) * SIN(lat * PI() / 180) + COS(%s * PI() / 180) * COS(lat * PI() / 180) * COS((%s - lon) * PI() / 180)) * 180 / PI()) * 60 * 1.1515) AS distance FROM app_car WHERE price BETWEEN %s AND %s HAVING distance<=%s ORDER BY distance ASC" cars = Car.objects.raw(query, [lat, lat, lon, min_price, max_price, miles]) return HttpResponse( cars )然后它的返回值是Car_Deferred_model_id_user_id ...

提问我正在学习django/python，并被一个问题给卡住了。我有一个视图：create_document.py，我想在其中计算模型类NameDetails中的名字细节数量。但我不知道正确的写法！这是我models.py的代码：class NameDetails(FillableModelWithLanguageVersion): user = models.ForeignKey(User) name_details_prefix_title = models.CharField(null=True, blank=True, max_length=25) name_details_first_name = models.CharField(null=False, blank=False, max_length=50) name_details_middle_name = models.CharField(null=True, blank=True, max_length=100) ....这是我create_document.py的代码，里面用 ...

我有一个Django模型，它之前是这样的class Car(models.Model): manufacturer_id = models.IntegerField()然后还有另一个名为Manufacturer的模型，id字段所指的就是它。然而，后来我意识到使用Django自带的外键功能，会更方便。因此，我将这个模型改为现在这样class Car(models.Model): manufacturer = models.ForeignKey(Manufacturer)这次修改似乎一下就弄好了，查询出来的结果也没有任何报错，但是当我试着运行数据迁移的时候，Django输出了以下结果- Remove field manufacturer_id from car - Add field manufacturer to car执行这个迁移会清除所有已经存在于数据库里的关系，所以我并不想这么做。我其实并不想做任何的迁移，毕竟像Car.objects.get(manufacturer__name="Toyota")这样的查询没有一点问题。我更想要一个恰当的数据库外键限制，但不是高优 ...

In Django, __icontains and __in are field lookups to the QuerySet methods. __icontains is a case-insensitive containment test, and __in means that the field is in a given iterable. So I would like to do the following lookup:keywords = ['How', 'to', 'setup', 'PrismJS', 'and', 'Autoloader', 'plugin', 'with', 'Nuxt', '3?'] #Possible keywords of title Writings.objects.filter(title__icontains__in=arr)Unfortunately, we can not combine field lookups in Django. To implement our desire, we can use Q() ob ...

我使用的版本是Django 4.2，有一个模型里定义了ImageField，以下面这个为例：class Example(models.Model) image = models.ImageField( blank=True, upload_to=my_image_path, )当我上传图片的时候，django返回了这样一个错误：Ensure this filename has at most 100 characters (it has 107)。在django文档中，我们可以发现：FileField 实例在数据库中被创建为 varchar 列，默认最大长度为 100 个字符。与其他字段一样，你可以使用 max_length 参数改变最大长度。并且要知道ImageField是FileField的子类：继承 FileField 的所有属性和方法，但也验证上传的对象是有效的图像。ImageField 实例在数据库中创建为 varchar 列，默认最大长度为 100 个字符。与其他字段一样，你可以使用 max_length 参数改变 ...

Django启动服务器的命令runserver，其实也是启动了一个自带的uwsgi服务。如果想要一直在后台不停的运行django项目，需要部署uwsgi服务器。uwsgi安装官方文档：安装uWSGI — uWSGI 2.0 文档 (uwsgi-docs-zh.readthedocs.io)可以直接用pip安装uwsgi：pip install uwsgi在django项目根地址，即跟manage.py同目录下新建配置文件uwsgi.ini，如：mysite1/uwsgi.iniuwsgi.ini必须以[uwsgi]开头，内容如下：[uwsgi] chdir=/mysite1 module=mysite1.wsgi:application socket=127.0.0.1:8000 master=True pidfile=uwsgi.pid vacuum=True max-requests=5000 daemonize=uwsgi.logchdir为django项目根地址，socket为django启动服务器的ip地址，daemonize为日志地址。注意，每个django项目中自动生成一 ...

When your views.py is too large, it becomes much more difficult to manage your code. So you might want to split views.py into several subviews, each of which contains a single sort of views.To split views.py, you could follow the following steps. Your original views.py might look like this:import ... def view1(request): pass def view2(request): passNow, create a new folder subviews aside with views.py , i.e. /Django/mysite/MyAPI/subviews. Next, create __init__.py, viewsa.py, and viewsb. ...

Suppose that we have two different models.class Author(models.Model): name = models.CharField(max_length=50) class Article(models.Model): title = models.CharField(max_length=100) author = models.ForeignKey(Author)In certain circumstances, you might want to merge two querysets into one queryset. For example, you may want to combine Author.objects.all() and Article.objects.all(). You could accomplish this by pure python method itertools.chain, or using Django's inbuilt queryset method ...