Python 一个属性正在更新，另一个属性未更新

我正在阅读，并试图进行练习。这项工作是：

更新填充脚本，使Python类别有128个视图和64个喜欢，Django类别有64个视图和32个喜欢，而其他框架类别有32个视图和16个喜欢

所以，我在人口脚本中也做了同样的事情：

def add_cat(name,likes,views):
c = Category.objects.get_or_create(name=name)[0]
c.likes = likes
print c.likes
c.views = views
return c

整个剧本是：

  import os
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'tango_with_django_project.settings')

import django
django.setup()

from rango.models import Category, Page


def populate():
    python_cat = add_cat('Python',64,128)

    add_page(cat=python_cat,
        title="Official Python Tutorial",
        url="http://docs.python.org/2/tutorial/")

    add_page(cat=python_cat,
        title="How to Think like a Computer Scientist",
        url="http://www.greenteapress.com/thinkpython/")

    add_page(cat=python_cat,
        title="Learn Python in 10 Minutes",
        url="http://www.korokithakis.net/tutorials/python/")

    django_cat = add_cat("Django",32,64)

    add_page(cat=django_cat,
        title="Official Django Tutorial",
        url="https://docs.djangoproject.com/en/1.5/intro/tutorial01/")

    add_page(cat=django_cat,
        title="Django Rocks",
        url="http://www.djangorocks.com/")

    add_page(cat=django_cat,
        title="How to Tango with Django",
        url="http://www.tangowithdjango.com/")

    frame_cat = add_cat("Other Frameworks",16,32)

    add_page(cat=frame_cat,
        title="Bottle",
        url="http://bottlepy.org/docs/dev/")

    add_page(cat=frame_cat,
        title="Flask",
        url="http://flask.pocoo.org")

    # Print out what we have added to the user.
    for c in Category.objects.all():
        for p in Page.objects.filter(category=c):
            print "- {0} - {1}".format(str(c), str(p))

def add_page(cat, title, url, views=0):
    p = Page.objects.get_or_create(category=cat, title=title)[0]
    p.url=url
    p.views=views
    p.save()
    return p

def add_cat(name,likes,views):
c = Category.objects.get_or_create(name=name)[0]
c.likes = likes
print c.likes
c.views = views
return c

# Start execution here!
if __name__ == '__main__':
    print "Starting Rango population script..."
    populate()

现在，我要打印喜欢和视图的值：

>>> c = Category.objects.get(pk = 3)
>>> c
<Category: Python>
>>> c.likes
0
>>> c.views
128
>>> 

>c=Category.objects.get（pk=3）
>>>c
>>>c.喜欢
0
>>>c.观点
128
>>> 

---

当视图更新时，likes的值不会更改

您需要保存对象，有关详细信息，请查看

---

请解释一下。为什么我需要为喜欢而不是视图保存？您正在保存

c

对象（它同时保存

likes

和

views

每个对象的属性），但是不保存视图就可以了。为什么它适用于视图？@learner通过执行

c.likes=likes

和

c.views=views

您正在为该范围更新

c

对象，您没有持久化该数据，您需要调用

.save（）

方法在数据库上写入并在更新后检索更新的值。

def add_cat(name,likes,views):
    c = Category.objects.get_or_create(name=name)[0]
    c.likes = likes
    print c.likes
    c.views = views
    c.save()
    return c